Yes, we've done it! We were able to get windows Server 2003 running on EC2. Here is the screen shot of the remote desktop connection.

Our approach is also compatible with most modern operating systems (Win, *Bsd, *nix, Etc) as well as VMware images. Windows is surprisingly responsive and would be more then capable of hosting applications.

See > http://www.enomaly.net/win_ec2.1136.0.html

Once we get approval from Amazon, we'll be releasing a tutorial and sample AMI, hopefully sometime over the next couple weeks.