We package our application as a .war file, we advertise support for JBoss AS5 and instruct our clients to copy the .war into their JBoss \'deploy\' directory, and start up their
There is a web interface that's fairly easy to use. You can access it after JBoss AS7 has been started by going to http://localhost:8080. There is a link on that page that takes you to the administration console.
You could also write scripts for deployments using the CLI interface. There is some information here https://docs.jboss.org/author/display/AS7/Management+Clients about how to use it.
Lastly you can always write your own Java client to deploy applications. I wrote a blog post a while back on how to write a custom deployment CLI interface.