The other day Microsoft showed off some simple apps and mentioned that source code would be coming for them. We now have some additional XNA source code for the devs out there to play with.
This sample for Windows Phone demonstrates using the Accelerometer sensor in XNA Game Studio 4.o as well as supplies an Accelerometer wrapper that can be used to easily implement Accelerometer functionality in your games
This sample for Windows Phone demonstrates Sphere to Sphere and Sphere to Plane physics through use of the Accelerometer
This updated sample for Windows and Windows Phone shows how an AI can use fuzzy logic to make decisions. It also demonstrates a method for organizing different AI behaviors, similar to a state machine.
This sample demonstrates a technique for using the touch panel to provide thumbstick-style controls for a game on Windows Phone.
This sample demonstrates basic navigation using waypoints. Waypoints has been updated to support touch controls on Windows Phone.
This updated sample for Windows and Windows Phone shows how to implement sprite sheets, combining many separate sprite images into a single larger texture that will be more efficient for the graphics card.
This Stock effects sample for Windows provides source code for the five effects (BasicEffect, SkinnedEffect, EnvironmentMapEffect, DualTextureEffect, and AlphaTestEffect), and the default shader used by SpriteBatch (SpriteEffect), built into the XNA Framework. There also is a command-line utility (CompileEffect) that uses the Content Pipeline to compile a .fx source file into a binary blob that can be passed directly to the XNA Framework Effect class constructor.
Content Manifest Extensions
This sample for Windows shows how to build a list of deployed content for your game to use.
There are also some videos located here at Vimeo.