BizTalk Links
Links taken from http://pluralsight.com/wiki/default.aspx/Aaron/TheBiztalkWiki.html

MSDN Sites
BizTalk Server Developer Center
BizTalk Server Community
Biztalk Webcasts
MSDNTV
Developing for Biztalk Server 2004 Inside Visual Studio .NET
Building Your First Business Process
WSE 2.0 Adapter for Biztalk Server 2004
Advanced Orchestration Concepts in Biztalk Server 2004 - Convoy Processing
BizTalk Server and 'Indigo'
Installation Guides
Microsoft BTS 2004 Installation Guide
The Quickstart Guide to Installing & Configuring BTS 2004 for Windows Server 2003
The Quickstart Guide - Multi-Box
BizTalk Installation Troubleshooting
Updating a VPC Biztalk Install
Extra Downloads / Utilities
Official Product Updates (SP1, ODBA, updated documentation, SDK refresh, etc)
BTS 2004 Adapter for Web Services Enhancement 2.0
BTS 2004 Adapter for MSMQ v2.0
BizTalk Partner Adapters
BizTalk Assembly Viewer
BizTalk 2004 Management Tool
BizTalk Server 2004 Performance Tool
Samples
Enhanced Validator Sample
Jon Flander's Samples
Whitepaper Listings
Microsoft Whitepapers - Published
Microsoft Whitepapers for Community Review - MSN Groups
Recommended Whitepapers / Articles
Understanding BTS 2004
Developing a BTS Solution
BTS 2004 Internals (awesome stuff)
BTS 2004 Web Services
Using XML Schema in BizTalk
Security in BTS 2004
What is BPEL?
Implementing Process Integration - PAG
Developing Integration Solutions with BTS 2004
Authoring Adapters
BizTalk Server 2004 Performance Characteristics
BizTalk Server 2004 Technical Guide for High Availability
BizTalk Server 2004 Convoy Deep Dives
Microsoft Biztalk Blogs
The Blogger's Guide to Biztalk (an aggregation of numerous blogs)
Microsoft Community Blogs
Scott Woodgate
Michael Woods
Biztalk Core Engine Weblog
BizTalk Server Performance
BizTalk Chalk Talk
Biztalk Customer Response Team's Blog
MSDN Webcasts Weblog
David Hurtado's Integration Traces
Darren Jefford
Kevin Smith
Stephen Kaufman
Recommended Blog Entries
How messages work in BTS 2004 Orchestrations
Constructing BTS 2004 XML Messages
BizTalk's Pub/Sub
Receive Pipelines
Promoting schema properties into message context
MSMQT Testing / MSMQ Acks
EAI Using MSMQ, .NET, and BTS 2004
BizTalk 2004 Flat File Schema Tutorial 1
Remote HAT
Create an Encryption Functoid
Deployment Framework for Biz Talk 2004 Applications - based on NAnt
DTC Transactions in an Orchestration