Topshot,
The program is called Shooter. I provided the solver for that program, and assisted with some of the advanced features like spin drift and coriolis. It uses a point mass solver and matches JBM nearly perfectly. In other words, if you want to know what trajectory it will output, you can run JBM to see. Of course the interface it totally different. You can bring weather in from GPS, or blue-tooth link with a kestrel. The rifle and ammo libraries are very convenient and can be backed up online.
Of course I recommend this program, but if you have any specific questions about how it works I'll be happy to answer them.
Take care,
-Bryan
BTW, I've only had two droid phones, the HTC and the DroidX. For running the Shooter program, the only difference is screen size in favor of the X, however the HTC is plenty adequate.