[Facebook Developers] The Facebook Developer site is the starting point for learning how to develop an application for Facebook.
[Visual Studio Express with Facebook] Visual Studio Express Showcase contains tutorial videos of step by step instructions for including Facebook in C# Windows Applications and C# ASP .NET webpages.
[C4F Vista Peer-to-Peer Toolkit] Codeplex offers a P2P toolkit for Facebook developers.
[Actionscript API for the Facebook platform] Google-Code offers an API to access Facebook from AS3.
[Facebook Wiki] Another useful resource for developing Facebook applications.
[Exploring 3D in Flash] An example that Facebook could be applied to.