Integrating Commerce Server Orders with BizTalk Server
Jeff Lynch has written an excellent document explaining how to use Commerce Server 2007 BizTalk adapters.
The Article gives a good introduction to Commerce Server 2007 BizTalk Adapters, Adapter Setup and Configuration, Using the Orders Receive Adapter, Development Best Practices.
Jeff used Commerce Server 2007 when it was beta and migrated a Commerce Server 2002 site. For more details see Jeff's blog.