I think you would love to use the freeware Tactical glide computer
programm LK8000

In a few days or weeks the 1.20 version will be released.
It runs perfectly on PC/PPC2002/PPC2003/WM5/WM6... portrait or
landscape mode
I can say as a beta tester it is a great piece of software. Stable!
Fast! With great features, who are all very well tested.