I just bought the horusvision softeare for the handspring visor. I'll post results when I test it. I also looked at the horusvision scope - looks great for target but too busy for hunting...
They also have an AMAZING product I bought called the ANDLE COSINE INDICATOR
It comes is two types - gives you angle or the angle cosine (which is multiplied by the yards to target). I bought the angle indicator. I mounts on the side of your scope with a scope ring and when you aim at your target you read the angle.
I bought the angle version because I wanted to use it with the software. But the cosine would be good if your not putting the gun down and can do the math in your head.
Really really good!