This can be done in many ways. first check out my thread on "controlling relays with n900" im doing this right now using N.C.D usb 24 relay board connected to a mico atom pc in my trunk and remote desktop 1.7 on my n900. check these sites out and see if it helps. addition hardware will be needed.
remember all of this works separately from your car door lock, security systems.
I'd be very very tempted to try some of th things in that thread. It's just unfortunate how hard it is to get electronics parts in Australia (without being in the business). Locally the only stores that stock sell resistors at a $1 a pop... you can see why I'm hesitant to start any project.
Perhaps when I start up my new job and that way I can simply steal their stuff.
Perhaps when I start up my new job and that way I can simply steal their stuff.