How to reverse cellphone firmware
In order to get a list of all supported AT commands, you can just run AT+CLAC which will list just that. It is a standardized command which, although optional, I assume virtuall all manufacturers support. Sony-Ericsson phones (as well as other phones based on platforms from Ericsson/ST-Ericsson) also support AT* as an alternative command (with an optional numeric parameter for different output formatting (e.g. AT*2)).