What did you write the calculator apps in?
It should also work on WM5.
You can go to
http://www.microsoft.com/windowsmobi...s/default.mspx
for information on developing for Windows Mobile devices.
I use Visual Studio 2003 to do .NET CF 1.1 or Visual Studio 2005 to do .NET CF 2.0 with a WM5 emulator.