I have been using the iphone app C25k. AKA, Couch to 5K. Soon after I started Kat starting looking for participants in her virtual 5K. It was great motivation so I signed up. I have never run a 5K before and figured this was the best way to start. I would run by myself, less pressure, and post about my accomplishment. For some seriously cute images and an amazing look at her post-races eats:
http://cobyandliza.blogspot.com/2010/06/ready-set-robot.html