Ajaxy Chatroom with Google App Engine

I'd like a chatroom on my website, www.careercup.com. It should be hosted off Google App Engine, and loaded via javascript or an iframe, so that it can be trivially inserted into other websites. It should have the following features: 1. RSS Feed of chatroom history 2. No authentication. Users should get a random username. 3. List of all users in the room. 4. Timestamps for each message. 5. Colors easily customizable 6. Option to set a global password.