SensorLock is a locking program designed for the HTC Touch Diamond/Pro. Locking and unlocking is done by rotating the phone and unlike most other locking programs, it does not interfere with or remove focus from running applications. A great feature is when the stylus is pulled out when device is asleep, autolock no longer locks the device. I am using this application now and it works as advertised.

Check for new versions and download it here, http://forum.xda-developers.com/showthread.php?t=422871