Yes, there is, and it should have been done ages ago. Please help the process by committing to it. Lots of us have been waiting for a long time for this as people are starting to use Stack Overflow more and more for Joomla support rather than using the Joomla forums.
We need 13 more committers with a rep of over 200 on any other site
The Joomla Stackexchange site is now in public beta!
Now there is at http://joomla.stackexchange.com