It has almost been one year since my first post, which was about my Auto Lock Vista Sidebar gadget. However, this gadget was only available on Si-Mi. So today I have released it on Windows Live Gallery, here, to hopefully be able to be useful to more people. [Update 7 Oct 2011: Microsoft has retired the gallery, but you can still get the gadget from my SkyDrive]
Usage instructions are as follows:

The Auto Lock Gadget automatically locks the computer when the selected Bluetooth device is out of range. The intention is that the gadget is paired with a Bluetooth device, such as a phone, that is carried with you. When you walk away from your computer with your phone, the gadget will automatically lock the computer, leaving it secure when you leave.

Before Using the Gadget

To get started you must create a pairing for your Bluetooth device to your computer.

1. Open the Control Panel

2. Select Hardware and Sound

3. Select Bluetooth Devices

4. Click Add… and following the Add Bluetooth Device Wizard

5. Once this is completed you are ready to use the Auto Lock Gadget

Using the Auto Lock Gadget

1. Drag the Auto Lock gadget onto your Sidebar or Desktop

2. Click the Discover Devices button

The drop down list will now be populated with your available Bluetooth

3. Select the device you want to connect to

4. Click the Enable AutoLock button

5. Now when your Bluetooth device goes out of range your computer will automatically lock