I originally released this some time ago, but did an update today that will help people who are running brushless motors. I added a calculator for when you know Spur, Transmission and your desired FDR, but need to find out HOW BIG of a pinion you need.
This should run on any PalmOS based device, if you want a cheap one look for a M105 on eBay, they can be had for about 20$ or less sometimes...
Anyways, here is the link to the program:
Here is a screen shot