AdFly is one of the oldest high-paying URL shorteners that not only has a really good reputation but a track record of paying its link shrinkers (users) on time and a great place for advertisers to spend their marketing budget.
Itiny.in URL Shortener - Free URL shortening & link management service Created by iTiny.in
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.
Kutt.it - Kutt.it is a free and open source URL shortener with custom domains and stats.
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.
PixelMe - URL shortener for savvy marketers