I have been using Winpilot, SeeyouMobile and XCSoar

I just want to point out the following regarding XCSoar. There is the
actual installation of the programm which is in my opinion reasonably
straight forward if you pick the right version for your PDA or PNA.
However the actual configuration of the programm is more tedious and
takes the time. You need to print out the manual and go through it
step by step and this admittetly is what is taking the time as the
choices in my opinion are more extensive than other programms.

Bruno