Q: Where can I download older or the newest release, "Release Candiate" or beta version of JBoss ? Are there other files I should look at ?
A: The JBoss project is partly hosted by SourceForge.net (https://sourceforge.net/projects/jboss). Go there and have a look at the Tracker, submit bugs or patches.
Least but not last there is the "Files" section with all the stuff you are looking for:
https://sourceforge.net/project/showfiles.php?group_id=22866