I am also looking for answer to this problem. Did you get the solution ?
At http://www.titan-books.com there is a workbook for jboss 3.0. It contains examples tailored for JBoss 3.0 from the Orielly press book Enterprise Java Beans 3rd Edition. It has an appendix the details how to set up jboss with Oracle. Only problem I had in it is where it said to put the driver in [JBOSS_HOME]/lib did not work. I had to put the driver in [JBOSS_HOME]/server/default/lib/