It took me 3 months to ID3 Tag all of the MP3s (artist, album, released year, etc) in my iTunes library. It was annoying. I saw that Winamp solves this problem with an "Auto Tag" feature. Is there a plugin for iTunes on OS X to do the same? Or does iTunes itself support this?
MusicBrainz Picard works quite well, it uses the same database as iEatBrainz but is still actively developed. It's free, and I've had great luck with it fixing tags on some 40GB of music I had laying around from my Windows days.
The interface is somewhat arcane unfortunately. Check out this link that will give you some other alternative ideas.
on edit: I went back to check out the newer version of Picard (0.12 vs 0.11), and the workflow is much improved. A lot of the annoying things from before have been automated. If you take a few minutes to set all the preferences to your tastes using the online help as reference, this really is a great automated tagging app.
iTunes does have a "Get Track Names" option under the "Advanced" menu. That should be what you're looking for. Granted it might not find everything, but it finds most of them.
If you aren't ripping from a CD, then I suggest iEatBrainz, though you will have to scrum up a UB for it.
There's also an application called SongGenie. It looks very good, too.
You could try TidySongs. From their website :
TidySongs is an easy and powerful program that will fix any missing or misspelled song details, add album artwork, remove duplicate songs and organize your music.
After many search I find TuneUp it's done what I want.
TuneUp is an easy-to-use and powerful plug-in for iTunes & Windows Media Player, and also available for both Mac and windows.
MetaBliss is good, but costs $20
You are limited to working with batches of 5000 at a time, but the bulk update feature is great