CM9 stable for Epic 4G was released a while ago at Cyanogenmod. Get the latest stable build from get.cm. The install instructions in our CM9 Install Guide still apply.
Update 12/21/2012: CM10.1 Preview for Epic 4G.
Update 9/29/2012: If you are running CM10, you will need the temporary FC09 utility v4 in order to update Profile and PRL. Thanks to mkasick and bbelos for fixing it!
The same team works on CM10, news is posted elsewhere on the Google+ page.