Pocket SMS is a program that allows you to control your mobile phone's messaging directly from your PC. You can write and send messages from Windows using the functions of your phone. It also allows you to synchronise contacts and view the messages sent and received as stored in the memory of your terminal.
It operates by communicating between a client you have to install on your phone and a server compatible with Windows. To initiate communication between the two programs, you just have to launch an ActiveSync synchronisation on your PC. Pocket SMS is an excellent solution to compose messages from your PC and send them via your device. However, I've never had a need to do that, which is, unfortunately, where I struggle to find a use for the software.