Lstu - A nice and open source url shortener. You can use it as service or install it on your own server.
1TinyLink - One Tiny Link allows you to reduce long links from websites such as Facebook, Twitter, YouTube, Linkedin as well as other sites on the internet for free.
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.
Akari Link Shortener - Anime-themed URL shortener.
Bitly - Get the most out of your social and online marketing efforts. Own, understand and activate your best audience through the power of the link with Bitly Enterprise.