This news is a little old now, I realised today that I forgot to post about it, but there are a whole heap of BizTalk Server Code samples that were released to MSDN back in June 06. http://msdn.microsoft.com/biztalk/downloads/samples/
Take a look at this list:
Publishing and Consuming Web Services with SOAP Headers
This sample demonstrates how to publish a BizTalk orchestration as a Web service with a SOAP header and how to consume the SOAP header from a Web service request message.
BAM and HAT Correlation
This sample demonstrates how to use the enhanced BAM features, and how to customize BAM and HAT integration. This sample also includes a Windows Forms application customizing BAM and HAT integration for the sample BizTalk solution.
Consuming Web Services with Array Parameters
This sample demonstrates how to consume Web services with array parameters.
Extending the BizTalk Server Administration Console
This sample demonstrates how to use the Microsoft Management Console (MMC) 2.0 Software Development Kit (SDK) to extend the functionality of the BizTalk Server Administration console with your own custom menu items, node items, new data items and views, or different views of existing data.
Viewing Failed Tracking Data
This sample uses Windows Forms to provide a simple interface to view and resubmit failed messages.
Inserting XML Nodes from Business Rules
This sample demonstrates how to insert nodes into an XML document and set their values from a business rule by using the XmlHelper class.
Using the Mass Copy Functoid
This sample demonstrates the use of the Mass Copy Functoid to map a source hierarchy to a destination hierarchy without mapping each individual element by hand.
Using Role Links
This sample demonstrates how to use role links and parties.
Split File Pipeline
This sample uses the FILE adapter to accept an input file containing multiple lines of text into a receive location.
Using Enterprise Library 2.0 with BizTalk Server
This sample demonstrates how to use Enterprise Library 2.0 with BizTalk Server.
Consuming Web Services
This sample demonstrates how to consume Web services in a messaging-only scenario, and without using the Add Web Reference option.
This sample consists of a C# console application that instantiates and hosts an instance of the receive adapter. The adapter is a Visual Studio 2005 class library that invokes the BizTalk Server 2006 APIs.
This sample demonstrates how acknowledgments work and how to use delivery notification.
Using Long-Running Transactions in Orchestrations
This sample demonstrates how to use long-running transactions in orchestrations.
Using the Looping Functoid
This sample transforms catalog data from one format to another by using the Looping functoid.
Mapping to a Repeating Structure
This sample demonstrates how to map multiple recurring records in an inbound message to their corresponding records in the outbound message in the BizTalk Mapper.
This sample demonstrates how to design the parallel convoy pattern in BizTalk Orchestration Designer.
This sample demonstrates how to invoke a policy from another policy by calling the Execute method of the Policy class exposed directly by the Microsoft.RuleEngine assembly.
Recoverable Interchange Processing Using Pipelines
This sample demonstrates how to implement recoverable interchange processing.
Using the Table Looping Functoid
This sample demonstrates the use of the Table Looping functoid in gated and non-gated configurations.
Using the Value Mapping and Value Mapping (Flattening) Functoids
This sample demonstrates the use of the Value Mapping and Value Mapping (Flattening) functoids to transform data between different message formats.
Direct Binding to an Orchestration
This sample processes fictitious loan requests using orchestrations with ports that are directly bound to another orchestration
Direct Binding to the MessageBox Database in Orchestrations
This sample processes fictitious loan requests using orchestrations with ports that are directly bound to the MessageBox database.
Using a Custom .NET Type for a Message in Orchestrations
This sample processes fictitious customer satisfaction survey responses from clients who spend time at different resort properties. Clients assign an overall satisfaction rating and can optionally enter a contact address and request a personal response. A request for a personal response generates a new message that is forwarded to a customer service application for tracking and follow-up.
Writing Orchestration Information as XML Using the ExplorerOM API
The sample performs two tasks. First, it writes configuration information for all orchestrations defined for a BizTalk server into a user-specified XML file. It then optionally transforms the XML data into a simple HTML report. This is accomplished through a console application.
Correlating Messages with Orchestration Instances
This sample receives a purchase order (PO) message from a fictitious customer and processes the purchase order message using correlation.
SSO as Configuration Store
This sample provides an implementation of a sample class and a walkthrough that demonstrates how to use the SSO administrative utility and the SSOApplicationConfig command-line tool.
Atomic Transactions with COM+ Serviced Components in Orchestrations
This sample demonstrates how atomic transactions work in orchestrations.
Exception Handling in Orchestrations
This sample demonstrates how to handle exceptions in an orchestration.
Implementing Scatter and Gather Pattern
This sample demonstrates how to implement the Scatter and Gather pattern using BizTalk Orchestration Designer.
Using the SQL Adapter with Atomic Transactions in Orchestrations
This sample shows how to use the SQL adapter with atomic transactions to keep databases consistent.