Patrick Stach has announced the availability of his source code for finding MD5 collisions and MD4 collisions (Coral cache links provided to prevent slashdotting). MD4 collisions can be found in a few seconds (but nobody uses that any more), while MD5 collisions (still being used!) take 45 minutes on a 1.6 GHz P4.
Yeah, it's kinda old news; but MD5 is still used extensively in the realm of bittorrent! The fear is that fakes will flood torrents and render them useless (I wonder who's a big enough jerk to do that... One name comes to mind). Fear not, however, a lot of clients including Azureus and BitComet use SHA-1 hash functions.