Should you lose your Windows Phone, there is a possibility that should a person come across it they'll return it. But what if there's a lock on the handset? They can't rummage around your Twitter, Live, email and Facebook accounts in attempt to contact you. This is where WP7 Lock Screen comes into play.
Waking up the screen will present whoever has picked up your phone with a wallpaper that's customised with your contact details so they can easily get in touch, whether it be via Twitter, Facebook or a landline number. An optional add on is a "cash reward" message at the bottom of the wallpaper, providing a small incentive to return the lost valuable.
Think of it also as a portable, digital business card that you don't have to keep in your wallet. It's a neat little idea. The pack, by AJ Troxell, is freely available at the source below and includes a .PSD file for customisation.
Source: AJ Troxell Thanks AJ!