We just moved into SOMAcentral, which is a hot startup space in SoMa for 40 startups, most with private offices. The fine folks over there offered us a sweet way to lock & unlock our office door - a new YCombinator-funded startup called Lockitron (no info on their public website yet).
They have an alpha product that connects an iPhone app up to the door lock, allowing us to lock & unlock our office door from anywhere in the world.
It's pretty amazing and it's brand new; you won't find anything on the 'net about it yet, but it's real and we are using it!
Below is a video of Lockitron in action. If you're interested in getting this set up for your home or office just contact me and I'll introduce you to one of the founders.