There's a YC company alternative: https://www.cloudkick.com/
Personally, I've found making my own utilities for AWS to be trivial, so that's what I do.
Besides that there is AWS tools which is a single Perl script, powerful enough the replace a lot of EC2 and S3 operation without any other dependency, I'm using that for shell scripts and manual operations: http://timkay.com/aws/
S3cmd is good for syncing files on Cloudfront.
Elasticfox - http://developer.amazonwebservices.com/connect/entry.jspa?ex...
Amazon S3 Extension - https://addons.mozilla.org/en-US/firefox/addon/3247
Boto - http://code.google.com/p/boto/
Fabric - http://www.nongnu.org/fab/
S3cmd - http://s3tools.org/s3cmd
There are a few other good services/tools out there, but so far I haven't found any as full-featured as RightScale. (But I'm watching this thread for other suggestions, too.)
I wish their upper-tier stuff was less expensive and we'd experiment with it a bit more. Supposedly it's free for companies who are funded through YC, though.
If you do try it, let me know what you think.
On the expensive side there is RightScale. They have a lot more tools and good service, but like I said they are a bit pricey.
http://aws.amazon.com/eclipse/
The Amazon tools are good for working with J2EE apps on EC2 and the Rockstarapps tools are good for general application development but don't have EC2 management.