Gina,
Yeah, actually, iEatBrainz does work quite often, although you'll get some false matches - ranging from totally wrong to the right song but the wrong album (as some tracks appear on multiple albums), but you can manually hint some of those or leave them for manual tagging. It shows you it's results before you commit them to iTunes. It matches by "musical fingerprint" so it doesn't matter what's missing and as a minimum it'll fill in the track, track number, artist and album and often year.
It's free, so worth giving a go.
MusicBrainz.org is the internet face on the DB that iEatBrainz uses, so worth a visit for those tracks that just will not be matched.
I believe there are apps out there that assist with tagging - including, probably, on Doug's site - but I haven't tried them.