jEasy Extensible Proxy is a reverse proxy running in tomcat or any other J2EE container. The proxy should be interesting for anyone wanting an open source reverse proxy for a java container. Another good choice for a reverse proxy is mod_proxy for apache, however this requires that you have apache running so j2ep might be more useful if you are already using a java server.
So what is a reverse proxy you might ask yourself, well instead of reinventing the wheel I can give a good link describing mod_proxy.
The latest download links can always be found on our sourceforge project page but here are direct download links as well.