I’ve been trying out a few of the shortened url scripts out there for the last week or so. I’ve tried out the Short URL WordPress plugin. I’ve also looked at Yourls.org, which is available as both as a standalone script, and a WordPress plugin.
Lessn is a standalone personal url shortener written in php and mysql. Set up is simple, just create a database, plug in the database connection information and then upload the /lessn/ directory to your site. Lessn allows you to create shortened urls used in twitter as well as bookmarklets.