You better stop using your girlfriends or the dogs name as password for your WPA key on your access point, German computer sciencetist Thomas Roth has made a proof of concept on using Amazon’s EC2 cloud service for cracking WPA keys. By using Amazon’s EC2 service the brute forcing of simpler keys are now within reach for anyone.
Read more here;
http://stacksmashing.net/2010/11/15/cracking-in-the-cloud-amazons-new-ec2-gpu-instances/