Ow.ly - Shorten links, measure traffic, and demonstrate social ROI right inside the Hootsuite dashboard.
Polr - An open source URL shortener. A great non-profit and free alternative to bit.ly, TinyURL, or goo.gl.
YOURLS - YOURLS is a website that contains all the tools you need to create and launch your very own URL shortener. URL shorteners like bitly or TinyURL are fine for public use, but they offer limited options in terms of URL customization.
Lessn More - Lessn More is a fork of Lessn with support for more types of short URLs than Lessn supported;...
Ai6 - Simply place your link into the form box and click the shorten button in order to get your compressed link for your page or marketing campaign.
Qlink.me - Link shortener and expander