There have been a couple of questions about URL rewriting. It is important when you want a web crawler to index your dynamic site as web crawlers normally will not index content that looks like it is generated dynamically.
The technical note provides an example of one way to fool a web crawler into thinking a site has static content. The example shows how Apache 2.0 can be used to transform a "static looking" URL back into a URL containing a query that is forwarded to Tomcat or Jetty. I hope it makes sense and is of use. The document is at http://www.amitysolutions.com.au/documents/URLRewriting-technote.pdf