If you are looking for the on-demand web casts for 2004, Scott Woodgate posted the links in his blog:

    1. MSDN Webcast: Getting up to speed with BizTalk Server 2004 for the Visual Studio .NET Developer
    1. MSDN Webcast: BizTalk Server 2004 Orchestration for the Visual Studio .NET Developer
    1. MSDN Webcast: BizTalk Server 2004 Architecture
    1. MSDN Webcast: BizTalk Server 2004 Performance and Early Adopter Experiences
    1. MSDN Webcast: Using Web Services with BizTalk Server 2004
    1. MSDN Webcast: BizTalk Server 2004 Business Rules for the Visual Studio .NET Developer
    1. MSDN Webcast:  Integrating BizTalk Server 2004 with SharePoint
    1. MSDN Webcast: Extending Mainframe Applications using BizTalk Server 2004 and Host Integration 2004