We have been using JBoss extensively in the last two years in order deploy GeoServer along with some custom extensions as well as a few other proprietary application. Lately we have started to experiment a bit with JBoss 5.x and since people seem to have problems deplying GeoServer in it weput together a post on our compay blog (see here) with some basic instructions on how to deploy GeoServer 1.7.6 inside JBoss 5.1.

If you you need help wrestling with JBoss, feel free to contact us!