I'm now a member of the CodePlex workspace for the Facebook Developer Toolkit. I've been working on porting across my modifications into the codebase. The .NETCF v2.0 version uses a project called Facebook.Compact but refers to the existing source files from the desktop project. Then some conditional compilation is used to hide a few unsupported features from .NETCF and implement some workarounds for missing functionality. This will be a familiar technique if you've been to Daniel's sessions (or read his blog posts on the subject). It's not quite working yet since my code made use of a couple of my own libraries for speed, so I'll need to implement a few of the features within those in the Facebook.Compact project.

The Facebook API allows third-party web and desktop applications to interact with Facebook features. There is an excellent shared-source library for .NET to wrap the Facebook calls but currently it only supports the full framework. I did some work converting this source to compile and run on .NETCF v2.0. There are some example screens here of the login process, and pulling back information about our book group.

Since the login screen uses the same page as the desktop it's not a great fit on a Pocket PC screen, so that's an area for improvement.