<p>Is there a way to run an Amazon EC2 AMI image in Windows?  I'd like to be able to do some testing and configuration locally.  I'm looking for something like Virtual PC.</p>

If you build your images from scratch you can do it with VMware (or insert your favorite VM software here).
Build and install your linux box as you'd like it, then run the AMI packaging/uploading tools
in
the guest. Then, just keep backup copies of your VM image in sync with the different AMI's you upload.
Some caveats: you'll need to make sure you're using compatible kernels, or at least have compatible kernel modules in the VM, or your instance won't boot on the EC2 network. You'll also have to make sure your system can autoconfigure itself, too (network, mounts, etc).
If you want to use an existing AMI, it's a little trickier. You need to download and unpack the AMI into a VM image, add a kernel and boot it. As far as I know, there's no 'one click' method to make it work. Also, the AMI's might be encrypted (I know they are at least signed).
You may be able to do this by having a 'bootstrap' VM set up to specifically extract the AMI's into a virtual disk using the AMI tools, then boot that virtual disk separately.
I know it's pretty vague, but those are the steps you'd have to go through. You could probably do some scripting to automate the process of converting AMI's to vdks.
The Amazon forum is also helpful. For example, see
this article
.
Oh,
this article
also talks about some of these processes in detail.