Which version of JBoss AS supports Java EE 6 (specifically JSF2.0)?
No one else supports Java EE 6. This can take several months. But JSF 2.0, in turn, is backward compatible with Servlet 2.5. This means that you can simply use JBoss AS 4.2 or later for this.
AS 6.0 will support Java EE 6. It is currently approaching Milestone 2. If you want to try JSF 2, it works fine in the current line.
Currently not and may take some time. Only Glassfish supports Java EE 6 right now
Following the instructions of http://aaron.ajexperience.com/2010/10/11/jboss-5-with-jsf-2-on-a-per-app-basis/ , you can use JSF 2 in JBoss 5.0.1 GA if you use Eclipse.