I assume you would be fine using the Oracle Thin Driver because these are the instructions I'll be giving to you.
1)Copy oracle-service.xml from <JBOSS-HOME>\docs\examples\jca and place it in <JBOSS-HOME>\server\default\deploy
2) Edit the following parameters in the above XML file:
<config-property name="ConnectionURL" type="java.lang.String">jdbc:oracle:thin:@serverdnsname:1521:dbinstancename</config-property>
Replace serverdnsname with you Oracle database server name. Replace dbinstancename with your Oracle SID.
b)<config-property name="UserName" type="java.lang.String">scott</config-property>
<config-property name="Password" type="java.lang.String">tiger</config-property>
Uncomment out these lines and add in the username and password if you want to use defaults.
3) Save the file. You should be ready to roll.
Oh, one other thing. Copy the classes12.zip file from your Oracle jdbc directory and put it in the <JBOSS-HOME>/server/default/lib directory. This is the Oracle JDBC Driver.
Thanks very much for your help, really appreciated.