GSM control project..help required!

Okay guys, I am very impressed with the knowledge base here and have done several hours of extensive searching on my own and am struggling slightly!
I would like a system where I can contact a vehicle through the gsm network and output a signal to an engine sub-system. The system will operate through a user calling the module in the vehicle then, after pin entry, a keypad entry from a mobile phone or landline will output a signal to an engine sub-system.
Does anyone have an idea how to go about this or what components I will need to do this?
Thanks for any input.
DirtDawg

You can buy a GSM modem from Sparkfun.com for not too bad a price. You will also need a micro controller to decode the keypad entry and talk to the modem. You'll have to do a bit of research on GSM modems - I'm not sure that they have both voice (for the keypad button presses) and data capability. Sparkfun.com also has a bunch of microcontroller kits to choose from.

Thanks for the reply, I will check that out.
DD