I'm interested in working on a small side project to roll my own short URL, similar to how TechCrunch recently unveiled their version of http://tcrn.ch/.
If you know of any detailed How-Tos for creating your own version of a short URL, I'd appreciate it.
(P.S. To keep the question on topic, I'm not interested in debating the merits of whether short URLs promote spam, acts as a middleman, etc as was covered some weeks ago here by joshu.)