Complete, lightweight and portable C# library for Facebook: gives complete access to Facebook functionalities (API, Chat and more), does browserless login and runs on Microsoft .net, Microsoft .net for Mobile (Compact Framework) and Mono.
On the 12th of February, 2009 I've received a "Cease and Desist" e-mail from Facebook's lawyers. As a result, the project will be closed at latest the 19th of February, 2009.
For now, the copies of that letter are kept personal. If you'd like a copy, contact me: http://contact.ali.tokmen.com/
It's been a great pleasure to work with such creative, realistic and helpful people.