The most consistent way to get that info would probably be some other website like wikipedia. If you're inclined, you can put that info into the comments section of iTunes for future reference.
So now that I download all of my music how can I get all of the details about songs and albums I used to get on liner notes with CDs? Stuff like who is playing what on each song?

Chowhound
Comic Vine
GameFAQs
GameSpot
Giant Bomb
TechRepublic