Samsung's Mobile Innovator program has released an SDK for Samsung specific APIs on their Windows Mobile devices. Although this is a native code SDK all the functions I looked at were very P/Invoke friendly. For example once you've installed the device-side cab you can query the luminance sensor using:-
[
DllImport("SamsungMobileSDK_1.dll")]
private static extern int SmiLightSensorGetIlluminance(out uint illuminance);
The exact features available vary depending on the device model but the SDK contains functionality for LEDs, Camera Flash, Light Sensor, Scroll Wheel, Accelerometer etc
You can download the SDK, and some Emulator skins for Samsung devices from here:-
http://innovator.samsungmobile.com/down/cnts/category.main.list.do?platformId=2&cateId=147&cateAll=all