[kavrick]

For the Mac & Non iPhone crowd there is also HandyLock (http://www.netputing.com/applications/handylock/) which is Donationware. Works great with my MBP and Nexus 5.

[duvnjak99]

Handylock is really cool and free but does not use the bluetooth LE. It will cost your battery..

[kolev]

Nice, although not nearly as polished.