I actually installed Reddit on a EC2 instance back in May from the official source code off of GitHub, so this definitely isn't something new.
On a related note, documentation for installing and maintaining Reddit is nearly non-existent. Very frustrating. I ended up taking the easy route and installed on a recommended Ubuntu image and used their Ubuntu-specific install script.
Here's the blog post: http://blog.reddit.com/2008/06/reddit-goes-open-source.html