I have decided to try BluePhoneElite, that I mentioned previously. I don't really want to use the SMS features, which it looks like is this applications main function. I am mainly interested in the proximity features. I just don't know if it is worth paying $20 for just this feature.
When I leave my desk, I want iTunes to pause, the status of Proteus to change to away, and my screen saver to activate. The iTunes and screen saver integration is built into BluePhoneElite. I wrote some AppleScripts to do the Proteus integration.
Here is the script that I use to set the status of Proteus:
I had to try out the different numbers to get the correct status to appear.