Yes, what you want to do is possible. You can write EJBs that are deployed to JBoss AS and then access them via JNDI from a standalone client. Do a Google search for "ejb standalone client" for examples.
However, that method is somewhat passe. You might be better off using web services (especially RESTful ones), deploy the web services to JBoss AS and have the standalone clients make web services calls. You'll also have a lot more options of the types of client you could write.