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. http://talk.maemo.org/showthread.php?t=47390