CommunityOne: Amazon EC2 and OpenSolaris
Sun is apparently poised to support Open Solaris on Amazon EC2. More information is available at http://sun.com/amazon. I've registered but haven't heard back. There are some limitations. The initial release only supports the 32-bit EC2 instances so that actually limits what you can do.
If I get a hold of the AMIs I'll try to post some notes on the experience.