Many songs are missing the correct album titles and cover art—or just show up in Apple Inc.’s (AAPL) iTunes with mysterious names like “Track04.” Over the years I’ve used several programs to import and buy music, resulting in wild inconsistencies in my collection. I’ve got songs by Beyoncé (with accent), Beyonce (without accent), Beyoncé Knowles (with accent) and Beyonce Knowles (without accent).

Several companies have developed programs that tap into vast databases of songs to tame music collections. I’ve been testing one by San Francisco startup TuneUp Media that’s available to download online and buy in Apple’s stores. While I was reluctant to pay $19.95 for a year’s subscription to a service I reckon should be in iTunes for free, TuneUp has largely delivered on its promise to scrub my music collection with minimal effort, making sure tracks were properly titled and adding extras like album cover art.

TuneUp’s greatest asset is that it works seamlessly with iTunes (for Mac and PC). With TuneUp hooked on to the right side of the iTunes program, you drag “dirty,” or mislabeled, songs into a box identified by a spray bottle of cleaner. The software identifies songs by taking clues from information you’ve embedded in your music, as well as sampling the song’s digital fingerprint. TuneUp looks for a match to those clues in a database of songs maintained by Sony Corp.’s (SNE) Gracenote.

Some matches are a slam dunk, but almost half of my collection proved to be problematic. Of the 500 most-played songs in my pop-oriented collection, TuneUp found “matches” for songs across 79 albums and “likely matches” for songs across 209 albums. It couldn’t identify 10 songs. The company says it counts matches as a 90% or higher chance of a match, and “likely” as at least 75% chance of a match. Songs with a likelihood under 75% are labeled “not found.”

TuneUp gives you the chance to review each of the matches before it adjusts your catalog. (It comes with an undo button.) Accepting all of the sure matches is easy enough, but slogging through the likely matches is troublesome. TuneUp gives you only the option to accept or reject its one recommendation after listening to the file, if you want.I worried that I might be inadvertently mislabeling a song, but haven’t yet found evidence of errors in my collection. The company says it cut out alternative matches to simplify the cleaning process, but is working on adding them to future releases of the software.

Once a song has been cleaned by TuneUp, it is given a consistent name, track number, album cover and other helpful information, such as the year it was released. Now I’ve got songs by just Beyoncé (with accent) and almost all of my songs feature the album cover art that looks so nifty on iPhone screens. The software assigns your songs genre identifications, which can be handy for matching music to your mood. Most of the classifications aren’t terms I would have come up with: Beyoncé is dubbed “urban crossover,” while Michael Jackson is either “disco” or “other pop” depending on the era—but at least they’re consistent. You also can tell TuneUp not to change any specific part of a song’s existing catalog listing, including genre.

TuneUp takes a few seconds, depending on your computer and Internet speed, to identify and re-classify each song. Attempting to scrub a whole collection—mine has more than 10,000 songs—can be a lengthy affair. The company suggests cleaning 500 songs at a time, but you can do many more than that if you leave it running over night.

I tried out a free competitor to TuneUp called MusicBrainz Picard, which matches songs based on a database collected by a swarm of Internet users, rather than one particular company. TuneUp and MusicBrainz, which is run by a nonprofit, are as different as Britannica and Wikipedia in their approaches to cataloging information.

The MusicBrainz approach to building a user-generated database is powerful and has been tapped by companies such as the BBC and Amazon.com (AMZN) to improve the way they keep track of music on their sites. Some of my songs that TuneUp couldn’t identify, such as the song “This Way” by hip hop group Dilated Peoples, were a breeze for MusicBrainz. To date, MusicBrainz has about 700,000 “releases” (such as whole albums) and 8,000,000 individual “tracks” in its database.

But MusicBrainz’s database has limitations, such as the inability to catalog album-cover images or song lyrics, both of which are copyrighted material. The free Picard program lets you tap the MusicBrainz database from your own computer. Serious music fans will be attracted to Picard because it is more precise than TuneUp; Picard guides you to choose from a variety of options when it isn’t certain of a match. But the software is rudimentary and requires concentration and time to use. Picard also doesn’t connect directly into iTunes’ catalog. To use it with iTunes, you have to first clean up all of your music files with Picard and then re-import your songs into iTunes.

I recommend TuneUp for the average music fan who might view cleaning up a music collection as the sort of task that shouldn’t take much longer than one rainy Sunday afternoon. Picard is better for people for whom maintaining an orderly music collection is a never-ending project.

TuneUp comes with a feature called “Tuniverse,” which fills the right side of the screen with information related to whatever song iTunes is playing at the time. That information includes YouTube videos, biographical details from Wikipedia, Google (GOOG) News, music recommendations from Amazon and tickets from StubHub to coming concerts in your area. While I initially worried Tuniverse would feel like added advertising on the screen, I’ve come to enjoy the extra information. And once again, I was left wondering why Apple hasn’t built these capabilities directly into iTunes. I, for one, learned from Tuniverse that Beyoncé has a concert in San Francisco next week, and I just might buy a ticket.

Walt Mossberg is on vacation.

Write to Geoffrey A. Fowler at Geoffrey.Fowler@wsj.com

The first approach uses a feature called Boot Camp that comes free on every new Mac. Using Boot Camp, the entire Mac is turned into a Windows PC, with the full capabilities and speed of a standard Windows machine. No trace of the Mac operating system is left running. The downside is that you can’t run Windows and Mac programs side by side.

The second approach uses one of two third-party programs to create a virtual Windows PC inside your Mac. This faux Windows machine runs at normal speeds and can operate simultaneously with the Mac’s own operating system. Programs native to each operating system can run side by side. The downside is that, because Windows doesn’t get complete control of the computer’s hardware, it isn’t quite as fast as in Boot Camp, and a few of its functions, like 3D graphics, don’t work as well.

This latter method is enabled by two excellent, closely matched $80 programs: Parallels, from a Swiss-based company of the same name, and Fusion, from VMWare, a U.S. company. It is Fusion that just got better, because VMWare just issued version 2.0 of the product with lots of new features, some of which let it catch up to the older Parallels and some of which push it ahead.

I’ve been testing Fusion 2.0 for a couple of weeks on two different Macs, and using it to run both Windows XP and Windows Vista. My verdict is that while you won’t go wrong with Parallels, Fusion edges it out as the better product.

The new Fusion 2.0 is a free upgrade for owners of version 1.0. It can be obtained at vmware.com/mac and at various retailers.

Like Boot Camp and Parallels, Fusion requires you to obtain and install a fresh, boxed, full version of Windows on your Mac. But once you’ve done that, your Mac becomes two computers in one. If you need to run programs that are available only on Windows, you can do so with ease.

For instance, as I write this column on a MacBook pro laptop, using a Macintosh word processor, I am using Fusion 2.0 to simultaneously run Google’s new Chrome browser, which is so far available for Windows only. I can switch between the two with a couple of keystrokes and copy text from one to the other.

Like Parallels, Fusion allows you to run Windows programs in one of three ways. You can see the entire Windows desktop, with Windows programs running within it, inside its own window on your Mac. Or, using a feature called “Unity,” each Windows program can float free, as if it were just another Mac program, with the Windows desktop invisible. If you minimize a Windows program, it disappears into an icon in the Mac’s Dock, just as Mac programs do.

Finally, you can devote the entire screen to the Windows desktop and hide the Mac operating system entirely.

Parallels can also do these things. Both programs can now also “mirror” your most common Windows and Mac file folders so that, for instance, all of the files in your Mac’s Pictures folder also appear in the My Pictures folder in Windows XP. This is a new addition to Fusion, as is the ability to take multiple “snapshots” of your Windows virtual machine, so if something goes wrong, you can roll back to a previous state when things were stable.

But Fusion has some other features Parallels lacks. For example, it allows you to automatically take those protective snapshots at timed intervals. It also permits you to completely customize keyboard commands so that the same common key combinations work in both Windows and Mac programs. It allows the faux Windows machine to take full advantage of multiple monitors, if you have them.

Fusion also uses a more modern and capable version of the proprietary 3-D graphics system in Windows, called DirectX. That means some Windows-only games and other programs that won’t work in Parallels will work in Fusion. I successfully tested two such programs, both from Microsoft: Worldwide Telescope and Photosynth.

And, in my experience, Fusion is a bit faster than Parallels. Both programs put a strain on your Mac when performing major tasks, like starting up or shutting down Windows. But Fusion seems to affect the Mac less. And, unlike Parallels, it can make Windows quicker by optionally assigning it control of the multiple “cores” in most modern processor chips.

Fusion also offers a one-year free subscription to Windows security software, while Parallels offers only a six-month subscription.

However, Fusion has its limits. Like Parallels, it cannot run the 3-D visual effects in Windows Vista. And, in my tests, it wouldn’t allow Windows running on one of my Macs to use the printer that was configured on the Mac, although that feature did work on my other test Mac.

In my view, Fusion is now the better choice for running Windows on a Mac virtually.

Find all of Walt Mossberg’s columns and videos online, free, at the All Things Digital Web site, walt.allthingsd.com.

Write to Walt Mossberg at mossberg@wsj.com

Amazon (AMZN) launched a new service called Amazon Video on Demand, which allows users, for a fee, to watch any of 40,000 TV episodes or movies, in real time, on their Windows and Macintosh computers, and on specially equipped Sony Bravia TV sets. This service replaces an earlier Amazon video offering called Unbox.

I have been testing Amazon Video on Demand and I found it worked well, although it has some limitations. The user interface is clean and smart, the quality is good if you have a fast Internet connection, and there are some clever features. On the downside, it works poorly with the slow connections typical in places like hotels. And there are some studio-imposed limits on what content is offered and how you can view it.

To date, there have been three major models for legally getting TV shows and movies from the Web.

In one, best represented by Apple’s (AAPL) widely used iTunes store, the TV shows and movies are ad-free, but you pay for each. All of this content is downloaded to your Windows or Macintosh computer or your Apple TV set-top box for later viewing, even when you’re not connected to the Internet — though on Apple TV you can start watching while the material is being downloaded.

A second model, best represented by the studio-owned Hulu.com, presents movies and TV shows on a Windows or Macintosh personal computer free of charge, but requires you to watch commercials that can’t be skipped. The TV shows and movies you view on Hulu are “streamed” rather than downloaded, meaning they are meant to be viewed immediately, in real time, rather than stored for viewing when you’re not connected to the Internet.

The third online model is best represented by Netflix (NFLX), the popular DVD distributor. It offers a “Watch Instantly” streaming option on Windows PCs or on TVs equipped with a special set-top box, for a small portion of its large catalog of TV shows and movies. These videos are ad-free and don’t carry an individual charge, but require a monthly subscription fee.

The new Amazon Video on Demand service is a hybrid of these others. As on iTunes, the TV shows and movies it offers are ad-free and purchased individually, don’t require a subscription, and work on both Windows and the Mac, plus on one type of set-top box. In Amazon’s case, that’s Sony’s Bravia Internet Link, a $299 device that works only with Sony (SNE) TVs.

But, like Hulu and Netflix and unlike Amazon’s older Unbox service, the new Amazon Video on Demand service offers videos via real-time streaming. In many cases, it also allows downloading, iTunes-style, to Windows PCs (but not Macs) and to TiVo devices attached to a TV. The videos can’t be streamed in real time using a TiVo (TIVO).

Amazon’s streaming videos are viewed in any of the major Web browsers and don’t require any special software. I tested the new service on both Windows PCs and Macs, and on a Sony Bravia TV equipped with the $299 adapter box. In my tests, Amazon’s videos looked quite good over a fast Internet connection. However, on a typically lousy hotel Internet connection, the movies were often grainy and kept stuttering.

The new service doesn’t yet offer videos in high definition, something Apple just announced this week it is adding for some TV shows. Amazon says it is working on HD.

Amazon’s user interface for the new service is very nice. All of your purchased videos are available in a library stored on the company’s servers, so you can easily watch them again and again if they are purchased, or resume a partly watched rental. And the service remembers where you stopped watching a video and resumes it at that point, even if you started it on, say, a Dell (DELL), and resumed it on a Mac.

On the downside, the new Amazon service isn’t always simple or consistent. For instance, you can watch only two videos at a time, and not all titles can be either streamed and downloaded, or be either purchased or rented. Most rentals last 24 hours, but some differ.

Selection was OK, but not great. Because of studio policies, many current and recent movie hits aren’t available. There are gaps as well in the TV selection. For example, while iTunes offers the current second season of the excellent “Mad Men” series, Amazon has only the first season.

Prices also can be confusing. Amazon rents most movies for $3.99 and sells them for between $9.99 and $14.99. TV shows generally cost $1.99. But some titles carry different prices, albeit these are often lower.

All in all, Amazon Video on Demand is a good service for people who prefer paying for ad-free TV shows and movies, and is another strong step in the Internet’s rising competition with traditional TV.

Find all of Walt Mossberg’s columns and videos online, free, at the All Things Digital Web site, walt.allthingsd.com. Email him at mossberg@wsj.com.