The system uses the iPhone's Bluetooth LE to connect with the smartlock. Simply walk up to your front door with your phone in your pocket, tap the lock, and turn the knob. Users and security are handled via iPhone and desktop apps that allow you to share keys with family and friends as administrative, normal or scheduled users.
Having someone house sit for you? Register their iPhone with the house for the week and never worry about them forgetting to return your key. Having family come into town to visit? No need to worry about having enough house keys to go around. You can even set on-off access in case someone needs to come by, but only once.
At the moment the system will only support the iPhone; Android and BlackBerry 10 support is on the way. Kevo is expected to go on sale soon. Head over to Engadget for their complete run down of the system, or check out the video below. Unikey is currently taking emails at their website for people interested in pre-ordering when the lock becomes available.