Yo.
With all that wacky internet-ness out there, the amout of music you can snag for free is getting freakin' ridiculous. I myself frequent:
http://www.kikapu.com (which features a release by Breaks The Blank Day; one of my bands)
http://old.uran97.com/index.php?GO=mp3 (thunderous drum and bass, from what I've heard so far... like this: ftp://ftp.scene.org/pub/music/groups/uran97/034/%5Buran97_034%5D_02_dq_-_take_that.mp3)
http://www.thinner.cc/pages/home.php (best dubtech/minimal label in the entire know universe)
etc. etc.
Are there any others that people like? I'm always on the lookout for new stuff, so give it up.
Cheer,
B