The Wireless Leash by Zomm is a helpful new gadget. It prevents you from forgetting your phone. You hook the "leash" onto your keychain and it forms a connection with the phone. If the two then become separated it will first vibrate, then flash, and finally sound an alarm to remind you to go back for it. It works with wireless phones that have Bluetooth functionality. It includes a number of other features such as a panic alarm, one-touch emergency dialing (works even if you can't talk to the operator), and a special amplifier that improves your speakerphone's performance when you use it hands-free while driving.
