"This sample demonstrates how to P/Invoke numerous useful native functions that are not directly available through the .NET Compact Framework. A test Form is provided that enumerates all available test procedures and allows the user to select and run them."
Geoff Schwab has a great collection of the most commonly requested P/Invoke functions. If you're a developer looking to play or record a .wav file, preform a soft reset, or maybe check the memory on your device you should give this article a read.
Note: These examples are based on the .NET Compact Framework 1.0. Some examples may not work in the Smartphone environment, like the controls for SIP. :wink: