Remote Control an Arduino using a GSM/GPRS shield.

First off, this is my first post on here and I hope that anything discovered through this thread will be useful to many people. I'd also like to thank in advance anyone that may be able to help.

Now, I have worked through all the basic examples of using the shield to send messages, make calls and even make the arduino do things on receiving a call and message. What I would like to do, is find a way to use the GPRS data connection to expose the serial terminal, which I can connect to remotely and send commands to and also view any data sent by the arduino from various sensors. I'm unsure whether I should be looking at sending commands this way or via another cell connection using a voice call to transmit data.

I hope someone a bit more experienced can shed some light on the matter.