Oh..dear!
Urm, how did you get into this little problem in the first place?
If you've ripped from CD's, CDDB will find the track names, artist, album, genre.. the lot.
To be honest, I would re-import all the CD's, and wait for CDDB to fill in all the information first.
They can't be music store downloads 'cos their already done, as are many of the File-shared MP3's people 'aquire'
Try and search on the net for something to find the track names, if you can fill in the artist and album before hand
(To do this just highlight the selected tracks, right click, and then 'Get Info')