A couple days ago an API for the accelerometer on the HTC Touch Diamond was reverse engineered by the Windows Mobile community.

Today, an application is now available that will enable tilt-sensitive orientation switching in all Windows Mobile applications!

MSmobiles has a video demonstration of this new program:

The program also allows you to specify which programs the automatic orientation rotation will function in, and of course you can disable it at any time. Another nice feature is you can set the device to shut off if you place it face-down on a table.

How cool is that?!

The GSEN program can be downloaded from here.