To install the datasource for MySql I have installed the jar in the folder "C:\jboss-as-7.1.0.Final\modules\com\mysql\main". Sure the directory is the same "C:\jboss-as-7.1.0.Final\modules\com"
I consulted this website: http://marceloagustini.wordpress.com/2011/09/23/agregar-mysql-datasource-jboss-7-x/
Thanks for the reply. At this point I'm not using data-sources so this doesn't seem to apply.
If your application is making direct JDBC connections, then it will need the driver class within the WAR's WEB-INF/lib subdirectory.
As has been noted by Wolf-Dieter Fink, this is not an application-server-like way of going about things; deployable applications are more modular if they use datasources provided by the execution environment, JBoss. This standardizes administration of datasource connection details.