How can I access a DataSource from Outside of JBoss (from a client)?
In JBoss-3.2.x you cannot, DataSources are not exposed remotely. There is an implementation of this in JBoss4. I would not recommend this anti-pattern.
In JBoss4, you can set the following attribute to false in the datasource definition:
Note: Exposing a Datasource remotely is NOT recommended, it's an anti-pattern. Also the connection manager in JBossAS is not designed to handle connection leaks which may occur when the client vanished or crashed.