Olá pessoal,
Alguns links que achei interessante sobre a utilização do WCF em conjunto com o BizTalk:
How a WCF Receive Adapter Processes an Incoming WCF Message
Windows Communication Foundation (WCF) Adapter FAQs
BizTalk Server and WCF Support in Visual Studio 2008
Using Custom Behaviors with the BizTalk WCF Adapters, Part 1
Using Custom Behaviors with the BizTalk WCF Adapters, Part 2