This week's book giveaway is in the OO, Patterns, UML and Refactoring forum. We're giving away four copies of Refactoring for Software Design Smells: Managing Technical Debt and have Girish Suryanarayana, Ganesh Samarthyam & Tushar Sharma on-line! See this thread for details.
The easiest way is probably have Tomcat handle the JSP and servlets, and Apache's web server or IIS handle the PHP. Check out http://tomcat.apache.org/connectors-doc/ - I've used it just yesterday to get one of our IIS servers to redirect calls to a Tomcat server. You can even have those running on different machines, as long as both have access to the worker and mapping definitions.