For EJBs to u need a container. And JBoss does provide that along with other components. Apache is normally bundled with most of linux distributions, but J2EE compliant app server still hasn't come out by default in various linux distributions , Even though Red Hat is pushing hard for Jonas, other opem source J2EE compliant app sever with their distribution.
I preusme it won't be far when Novell which owns SUSE now will start shipping JBoss with its distribution, as these guys have partnership now, and after IBM's buy out of GlueCode you dont know what JBoss folks will do now.
Anyway i hope this helps yr query.