Please remember that this is a rumor, and that a general dose of salt applies.
via Garanaul the Black
Just a quick release date tidbit before things fizzle out completely. It is from an excellent source (standard caveats apply of course, as nothing is ever certain). I've been told that Chaos is about six months from release, which is approximately late June / July, not sure if / how this is going to affect the release of 6th Edition.
I've been sitting on this one for about a week so if it's common knowledge, please ignore.
OT: Tau is being worked on, but further out than people think