Check out the cool Code Samples on BTS 2006 at MSDN:
Featured Samples

BizTalk Server 2006 Code Samples Collection
This file contains all of the BizTalk Server 2006 samples for easy download. It is updated as new samples are published.

Integrating BizTalk Server 2006 and Windows Workflow Foundation (BizTalk Server Sample)
This sample demonstrates how to integrate Microsoft BizTalk Server […]