Brewgyver:
Forgive an obvious question, but is this a house you own? If not, forget the whole idea.
I rent, but I don't see why this wouldn't be feasible. All I'm talking about is something that would mount above my deadbolt, and turn my deadbolt when I pressed some kind of key-fob when I was within site, or maybe even over the internet with a wireless router signal. Thanks for all your guys ideas so far, but I'm still not sure what I would need to start at all.
What kind of motors can you attach to an Arduino? Would a 9v battery suffice? What's the cheapest/easiest way to get an Arduino hooked up to either the internet over Wifi or some kind of near field communicator?
And I would obviously always have the key with me at all times in case of failure.