I was about to agree with everyone about this being a lazy question, but now I feel like an idiot because I never knew Amazon offered "AWS Identity and Access Management (IAM)" (http://aws.amazon.com/iam/), which is a godsend.

What's a shame is that right now there isn't a web-based GUI for this service yet, and the boto Python module's IAM support is currently undocumented, but at least the code is there. A bit of code reading to get it up and running.