the JBoss community version download page is here http://www.jboss.org/jbossas/downloads.
For difference between community and enterprise you will find informations here http://www.jboss.com/products/community-enterprise/
The EAP versions are supported and you need a subscription for this, all community versions are without support.
You may download a 30days trial version of EAP here http://www.jboss.com/downloads/
but ATM there is no EAP6 released, if you need a preview you might use the community version 7.x because this will be the base for EAP6.