Locate and Copy your JDBC driver into the server/$/lib directory!!

A comprehensive list of JDBC Drivers can be found at http://developers.sun.com/product/jdbc/drivers

Some popular ones include:

Oracle - http://www.oracle.com/technology/software/tech/java/sqlj_jdbc/index.html

MySql - http://www.mysql.com/products/connector/j/

Microsoft Sql Server 2005 - http://www.microsoft.com/downloads/details.aspx?FamilyID=c47053eb-3b64-4794-950d-81e1ec91c1ba&DisplayLang=en

Posgres - http://jdbc.postgresql.org/download.html

Data Direct Drivers - http://www.datadirect.com/products/jdbc/jdbc_jboss_certification/index.ssp?gclid=CJ7Oua7a7I8CFRAUQgodO2itNQ

Supported and tested drivers include these listed

Hibernate - http://www.hibernate.org/382.html

JBoss EAP - http://www.jboss.org/products/platforms/application/testedconfigurations