KDE 4.X and Blueproximity Screen Lock
Running openSUSE 11.4, with KDE 4.6, although this *SHOULD* work on any Linux distro with KDE 4.X.
Since this is about getting Blueproximity to work with KDE4, I'll assume you've already got a working Bluetooth adapter, and know how to pair a device. Also, this assumes you're using one of the KDE Screensavers.
Step one: pair whatever device you have in mind, with your workstation. Doesn't matter what it is, as long as it's paired. In my case, I'm using an iPhone.
Step two: Run blueproximity, and make sure your device is in 'Discoverable' mode. In the "Bluetooth Device" tab, click on the "Scan for devices" button...since your device is discoverable, it'll pop up in a second or two. Then select the device, and click "Use selected device".
Under the "Proximity Details" tab, set the Locking values to 7 and 3, and the Unlocking values to 3 and 2.
Here's where it gets interesting. Since blueproximity is a Gnome application, you've got to tell it to use KDE.
Locking Command - qdbus org.freedesktop.ScreenSaver /ScreenSaver Lock
Unlocking Command - killall -9 kscreenlocker
leave the proximity command alone. Click CLOSE. The app should minimize to the system tray, and you'll see it poll your device every now and then. To test it, you have to take your device away from your workstation, and sit it down...don't just turn Bluetooth on the device off. When you go back to your workstation, the screen saver should be running. To turn it off...go back and get your device, and walk up to your computer, and you should see the screen saver go back off.