There have been some updates to the relatively new project, EC2Box, which provides a web-based SSH console for managing Amazon EC2 instances. Check out the demo:
More about EC2Box:
EC2Box allows you to share terminal commands and upload files to all your EC2 instances. Once the sessions have been opened you can select a single EC2 instance or any combination to run your commands. Also, additional instance administrators can be added and their terminal sessions and history can be audited.
-- GitHub Page
Since EC2Box is forked from Netflix's Cloud-Prize, I'd definitely have a look.