When we first announced RHQ, we put the state of our internal svn repository at RHQ, but did not start right away committing new stuff into it.
Last night we switched over to the RHQ svn and added all the stuff that was developed since the first cut over.
So expect lots of changes going into it from now on.
If you don't want to check out the source, but just browse around, you can use the source viewer at http://www.rhq-project.org/svn.php.
Don't forget to checkout the documentation in the forums.
You can also meet developers on #rhq at irc.freenode.net.