This week's giveaway is in the EJB and other Java EE Technologies forum. We're giving away four copies of EJB 3 in Action and have Debu Panda, Reza Rahman, Ryan Cuprak, and Michael Remijan on-line! See this thread for details.
You can deploy any number of web applications on a single server instance (ofcourse it should have the necessary resources to handle that load). Just deploy them like you would have deployed a single application by placing it in the deploy folder of the server.