uxlabs@Microsoft has just released Fishbowl, a sample client application for Facebook, complete with source code. Fishbowl requires .NET 3.5 and uses WPF and ClickOnce. If you’re using Windows 7, it also demonstrates new features such as Jump Lists, taskbar previews, and multitouch.
You can get more information and install the application from http://www.fishbowlclient.com.
You can get the source code from http://fishbowl.codeplex.com.