Read the readme.html file, Configuration Issues section, first bullet under JBossAS 4.2.0.GA.
for lazy people as me
run.sh -b 0.0.0.0
but read this first
JBossAS now binds its services to localhost (127.0.0.1) *by default*, instead of binding to all available interfaces (0.0.0.0). This was primarily done for security reasons because of concerns of users going to production without having secured their servers properly. To enable remote access by binding JBoss services to a particular interface, simply run jboss with the -b option. To bind to all available interfaces and re-enable the legacy behaviour use -b 0.0.0.0. In any case, be aware you still need to secure you server properly.