Many PDC 2003 Sessions are posted publicly at this time. 
http://microsoft.sitestream.com/PDC2003/Default.htm

BizTalk sessions include the following:

1. DAT321 – BizTalk Orchestration Engine Futures (powerpoint)
   
2. DAT350 – Architecting End-to-End Enterprise Solutions: InfoPath with BizTalk 2004, SQL Server, “Indigo”, WSE and Line-of-Business Applications (powerpoint)
   
3. DAT420 – BizTalk Server 2004 with SQL Server “Yukon” DTS and “Indigo” (powerpoint)