Ok, here's an example...

I took six songs by Moxy Fruvous (great Canadian band). They were completely untagged. The filenames had the only info. They're named like the following:

Moxy Fruvous - Spiderman

When I do the lookup on them through MusicMatch, I get the attached screen. It grabs the top 5 matches from our database and automatically selects the best one. You can see that it mis-guessed on #2, but you can fix that by selecting the correct one.

When you're done, you say OK, and it applys all the track tag info to the tracks. There's also a command that can rename the files using the track info.

As for the data, it's our own database. We created it based on data from AMG (All Music Guide), which we use for our MusicMatch Guide.