I build Amazon AMIs. I started out building them on the actual Amazon EC2 infrastructure myself only to learn that doing so costs the runtime and the money on EC2. There is an easier way to get alot of it out of the way without it actually costing something.
My suggestion is to build a linux box in Oracle’s Virtualbox and then bundling and sending it to your S3 account for testing. I’ll do a write up of how to do this for the more technical minded, but in this economy, it’s a great way to save money.
The only cost you would incur is launching the instance for testing once you’re actually on the Amazon cloud.
After building over 50 images, I realized that I could do this and incur some serious savings.