This is a free ballistic calculator for use with Windows Excel and any pocket PC / Windows CE that has Excel installed. "Black Berry" "Windows Mobil smart phones"
FYI: you can pick up used "pocket PC's" cheep on ebay.
I got a new Dell Axim x-5 on ebay for $41.00. It is very fast and works great. There is also lots of cases, larger batteries and other stuff for them too. I loaded mine with the Perry Systems ExBal with no complaints. Very accurate info.