JBoss supports remote deployment, but unfortunately the two ways of remote deployment I know both don't create "persistent" deployments: the next time the server reboots, the app is gone.
So, the best way is to copy the file to the remote jboss e.g. through a network share. You might even share the deploy folder directly.
JBoss 4.2 contained a "MainDeployer" MBean which supported remote deployment as far as I know, but this one became obsolete in 5.0. I am not sure whether there is something new in 5.x.
The only approach left is JSR88 (which will not create persistent deployments): http://community.jboss.org/wiki/JSR88Client