Schlage has had this for a while. I think their iPhone app has been working for 2+ years.

And I would guess they have a patent to show for it.

Confirmed. Schlage has a relevant patent.

Kwikset also sells an iphone enabled lock, but an extremely cursory search didn't turn up a patent for them.

I wish them the best, but I'm having trouble coming up with a compelling argument to buy from them instead of buying what appear to be more mature, fully-featured products, backed by major lock manufacturers that are pretty well guaranteed not to go away in a year or two.

They should add a keypad as well for people without a phone. Keypad code gets set automatically for each Airbnb guest and expires automatically. This of course requies the Airbnb space to have an internet connection.

You could do this today with the Schlage system. It allows you to create a number of codes, and supports codes that work only during specified periods of time so a particular guest's keycode would only work for the duration of their stay.

How many Airbnb users do you expect to not own a mobile phone?

I often don't have a mobile or mobile number when I enter a foreign country.

We don't have the perfect solution to this yet, but we've been mulling the idea of key code locks for a while.

Current users who encounter this usually find some way to unlock their door for their guests after a phone call, leaving keys inside. The prevalence of affordable prepaid phones is helping to alleviate this issue.

I used AirBnb in Paris and my mobile didn't work. The host was gracious enough to send someone around to find the confused looking foreigners when she couldn't reach me.

It's not unusual for me to leave my phone behind when I go on vacation. That's part of the vacation.

I expect batteries to run out. You could have a usb port perhaps...

I was thinking the exact same thing. We just booked in a guest who wants to arrive while I'm at work so this would make life a bit easier.