-a friend of mine swears by http://www.moodlogic.com/
-i do it manually
-itunes will do it for you i think.
It all comes down to making sure their ID3 tags are good though. I think Moodlogic will take the ID3 tag first.. then try and sort it out by filename. Its worth your time to go through once and make sure all the tags are good, and then from there on make sure you update anything new.
edit: bah.. from the moodlogic forums it doesnt seem like a great choice
doing it manually is a very VERY daunting task. manually sorting what I rip from my CDs is easy enough; but I'm trying to deal with old mp3s I've had for years. A lot are duplicates...a lot don't have album tracks in their tags...
I might try itunes as a temporary solution...I just want to get everything sorted out...and as many gigs of unsorted as I have (I've been replacing what I lost when my old IDE RAID 5 lost a channel and crapped out).
I like to use mediamonkey, the player is based off of winamp i believe and the library functions are amazing. It has an option to retrieve id3 information using amazon.com which is a great feature. You can get the demo here: http://www.download.com/MediaMonkey/3000-2141_4-10403224.html?tag=lst-0-1