These days, I\'ve seen a URL pattern like this:
http://stackoverflow.com/questions/How-to-do
Not a usual and old one like this:
URL Rewriting can be achieved with PHP on Apache using the Apache mod_rewrite plugin and a rule definitions placed in a .htaccess file. Here's a guide.
On Tomcat 6 there is a popular URL rewriting utility called UrlRewrite.
What you want is Apache's mod_rewrite
Check this out: apache.org