WordPress now uses a Subversion Repository! Subversion is smooth, creamy and topped with a cherry.

Matt says everyone should do the following to use it anonymously (everyone except the devs can use the following instructions) :

svn co http://svn.automattic.com/wordpress/trunk/
…HACK HACK HACK…
svn status
svn diff > patch.txt
GOTO http://mosquito.wordpress.org and file that patch/bug!
svn update

Right now let’s put all code changes through mosquito. Something cool
about `svn diff` is it’s an offline operation, ie you can do it on a plane.

More details on using SVN here

There’s a mailing list with commit messages, in case you are interested. If you are subscribed to the old wp-cvs list, you do not need to subscribe again. This is a cool way to stay up to date with changes to WordPress.
So go ahead and subvert!