I think you can treat GF like any other JMS provider. There are “step by step” guides out there on the web for integrating MQSeries which would follow the same pattern for GF MQ; for examples, see blog links on the WebLogic Messaging Page http://www.oracle.com/technetwork/middleware/weblogic/messaging.
I don’t know if it would be better to use an adapter in your case, or to simply directly use an MDB, bridge, etc, as per the Integrating Remote JMS Providers FAQ - (http://download.oracle.com/docs/cd/E17904_01/web.1111/e13727/interop.htm#JMSPG553).
An adapter can sometimes be helpful in ensuring that an application is portable between between different app server providers, or it may have functionality in of itself that makes JMS easier to use with a particular layered product. The Oracle SOA product suite's JMS Adapter falls into this area.