An Enterprise application should be packaged in an EAR file (Enterprise ARchive). This is different from a Web application - which is packaged in a WAR file (Web ARchive).
Once you have the Ear file, you just copy it to the application server's deploy directory.
Note that if your enterprise application requires any resources that don't come with the application server by default, you will need to provide those. This includes among other things, database resource definitions, security configuration, etc.
There is a great book on the subject for JBoss, called JBoss in Action, by our very own Peter Johnson. It was a tremendous help to me in learning how to administer the JBoss application server, and configure it for the deployment of my applications.
If you're not sure how to package your application components into the Ear file, the Servlet Specification goes into all this detail, and is not as dry a read as you might expect a specification to be
And the first chapter for JBoss in Action is a free download and should give you all the information you need to know to deploy your WAR (the chapter steps you through creating and deploying a "hello world" WAR).