Remote start is one of those wonderful, pain-reducing inventions that keeps you from having to sit in an older car until the engine has warmed up enough. But if your car doesn't have a remote ignition, you can build your own remote start system that responds to a text message from an iPhone.
Tech pro Will O'Brien uses an Arduino, broken iPhone charger, an Avital 3117 remote start (current versions on Amazon are around $US40) and a few other items for this DIY project:
How it works in real life:
I send a text message from my phone with the phrase: "Start 1234″ (1234 would be the password in the phone script). The phone gets the text then tells the arduino via serial interface to start. The arduino grounds the wire to the remote start that activates it. Meanwhile, the phone sends back a SMS saying ‘Executed' to let me know that it got the message and is acting on it. In the future it'll send back a message confirming that the start was executed as opposed to the I told him to do it method.
There are a few cool thing about this SMS remote start: You don't have to carry around an extra block remote on your keychain, and the range is wider.
Will has posted the Arduino code and other fine details if you want to do this yourself.