This week's book giveaway is in the OCPJP forum. We're giving away four copies of OCA/OCP Java SE 7 Programmer I & II Study Guide and have Kathy Sierra & Bert Bates on-line! See this thread for details.
You can access it directly, i.e. through a client-side redirect, without problems. To get a RequestDispatcher for a different web app, you need to set the "crossContext" attribute (see the Tomcat documentation)