Shorty is a simple tool for creating shorter, human- readable links from long URLs. You install Shorty on your server, so the links you create with it never go away. You can also manage your links and see how often people click on them.
lilURL is a simple PHP/MySQL script for generating lil' URLs. It's similar to TinyURL, Shorl, MakeAShorterLink, etc, but you can run it on your own server. Requires PHP and MySQL. Supports mod_rewrite.