In the Panthon Group, they make a distinction of installing a preconfigured EC2 AMI stack or "rolling your own" using a very complex bunch of steps. See http://groups.drupal.org/node/50408It's not completely clear what the advantage of the self rolled method is. They reference BCFG2, and I'm still not clear on what that is. From what I gather, it's a system for updating Mercury configuration files from a remote repository. Just not sure. I will give it try later, but for now, I installed the Mercury AMI by following these instructions: http://paulstamatiou.com/how-to-getting-started-with-amazon-ec2Following this tutorial, I had my Mercury instance up and running in about 15 minutes! Not bad.