I just found a program called RPMsound. It listens to your engine and tells
you the RPM. I used this to verify my tach. It comes in versions for the
Windows PC and the PocketPC. http://www.tunelab-world.com/rpmsound.html

I also have a weight and balance spreadsheet in my PocketPC.

I have some flying music in my PocketPC.

Anyone else have some cool application for pilots?