Got an idea for a killer java app for mobile phones: a completely live letter-by-letter chat room engine. A java servlet runs the back-end server, and users download a small jad/jar file on their mobile. It asks them for a name and a preferred text colour (to distinguish users) before entering the room. Using the usual press 5 three times to get an L method, each individual character is sent to the server. This is instead of traditional IM clients that only send data after whole messages are typed (too clunky a method for mobile keypad entry). Would be handy if client remembered your nickname and other settings so you could just jump straight in. What do you think?