There's three different flavors of Windows Mobile in the 6.x line. Standard, Classic, and Professional.
Standard = Smart Phone, no touchscreen
Classic = PDA w/touchscreen
Professional = PDA / Phone with Touchscreen
One of the other interesting little gotchas is that the .Net Compact Framework 2.0 compiles the same for all three editions. Unfortunately, once in a while, you get a "NotSupportedException" out of the Standard edition.
A few days ago, in order to get my sudoku program published, I decided to simply avoid a problem I had with the Standard edition's lack of a SaveFileDialog and OpenFileDialog. My avoidance manifested in a "not supported" message of my own, if the user tried to save / load a file in that environment.
Today, I capitulated... I implemented an alternative file save/load functionality which kicks in automatically when the program gets a "NotSupportedException" on the common dialogs.
It's in 3.0.3, which I've re-published on PocketGear.