I am interested in implementing different aspects of chat with a server (based on ejabberd/scala - if any one have worked on it, otherwise app engine - we can use gcm to mock the chat server - though there are availability issues with it). Main point is to implement a frontend (list-view) with basic functionality, text storage in database (both local sqlite and on server some sql/nosql based database) and effeciently compressing and storing the images. Also interested in discussing about the security issues on transmitting the data over wire, login (may not be needed as permissions can be enough) .
Please feel free to add more ideas.