SLARToolkit is a flexible AR library created to allow the development of real time AR applications with Silverlight as easy and fast as possible. It can be used with the Webcam API that was introduced in Silverlight 4 or with any other CaptureSource or WriteableBitmap. SLARTookit is based on the established NyARToolkit and ARToolkit libraries.
SLARToolkit features include:
Direct Support for Silverlight's CaptureSource
Multiple marker detection
Simple black square markers
Real time performance
Documentation including a step by step Beginner's Guide
SLARToolKit can be downloaded from http://slartoolkit.codeplex.com/