Hotel Inn hotels is testing smartphones as hotel room keys.

The list of doors opened by smartphones just keep growing and this time, the smartphones are opening real doors, hotel doors that is. In a test run, the hotels chain Holiday inn has started using an mobile application developed by MobileKey and called OpenWays iPhone, Android and Blackberry smartphones to serve as hotel room keys. With the new system in test until December, hotel guests in the two test markets of Chicago and Houston, can reserve their rooms Online and receive a text message on their phones containing their room number and a link to unlock the door. When they arrive at the hotel, they won't even need to stop by the reception desk to pick up a key.
According to USA Today, people interested in the program, can sign up by making online reservations.

For more, see NewYorkTimes.com