Few days back I posted a tweak by which you can increase the scroll bar height and width in Windows Mobile for easy navigation.

Now a developer at XDA Forums have come up with an application/service with which you can scroll using the Diamond's Navigation Sensor Wheel.

Tried in my HTC Touch Diamond and it really works !!

You can get the cab installer at http://forum.xda-developers.com/showthread.php?t=466377

Tip: Don't Install in Internal Storage !!
When I connected my Diamond in Disk Drive Mode the app stopped working as Internal Storage is not accessible in this mode.