tracks for remixing ?

I am looking for songs that have been split into their individual tracks, but I don’t know what this is called, so I don’t know where to look.
For example: for a remix contest, a band sells a song to anyone who cares to participate, but every part of the song (vocals, drums, bass, guitar, keys ,etc.) is in an individual file on its own so that one can recombine and remix it with other stuff … I have a song by Marillion in that way but I am looking for more of this kinds of songs … How do I search for these ?? Any help appreciated.
Answer #1
If you are a Nine Inch Nails fan then you can find a bunch of them here:
http://remix.nin.com/
You might have to register (not sure as I am already a member) but it is easy to do. Once you are there (and signed in probably), click on MIX at the top left and then there will be a link marked DOWNLOAD MULTI-TRACKS. Other than Nine Inch Nails there are songs from Saul Williams, How to Destroy Angels, Jane’s Addiction, and Street Sweeper.
Other than that just do a google search for “Multitracks” and you will find some.