Like phone numbers, the days of physical keys are numbered in my opinion. It's time to make a bolt for the digital home of the future.
Here's an interesting product from American lock maker Kwikset called "Kevo." Kevo works in partnership with an iPhone via Bluetooth. The lock senses when an authorized iPhone is close by and then allows the lock to be opened with a simple touch. (The lock also works with a conventional key in case of emergency.)
This isn't the first electronic lock on the market, and there are even locks available which become part of the home network with the ability to alert the home owner of possible intrusions. But Kwikset (owned by Black & Decker) is one of many hardware companies which are pushing their wares into this young century with a digital twist. According to Mashable, Kevo will be priced around $250 without installation.
It's worth pointing out here that this is only iPhone-friendly, although there may be an Android app at some point. Once again, other platforms are getting locked out of the latest and maybe greatest products.