If you are an user of JBoss AS 5.1, then you should upgrade to the latest JBoss AS6 which was released recently. Apart from the regular bug fixes, you also get the Java EE 6 certified Web Profile...
More information is in Rich Sharples's blog post. JBoss AS 6 Released !
Happy EE coding!
If you need more info on EE6 development, do sign up for Pete Muir's Jan 19th webinar. http://www.jboss.org/webinars
Also additional info is given by Dimitris. http://dandreadis.blogspot.com/2011/01/introducing-brand-new-jboss-as-60.html