Microsoft just released BizTalk Server 2009. It is the sixth release of this product. Here is a list of handy resources about BizTalk 2009.

Technical Overview

http://www.microsoft.com/downloads/details.aspx?familyid=1F839374-17DF-43B9-840E-60C11F20F42B&displaylang=en

Installation and Upgrade Guides

http://www.microsoft.com/downloads/details.aspx?displaylang=en&FamilyID=9c697e02-d1bc-4684-8748-28b3a292d5bf

Hyper V Guide

http://www.microsoft.com/downloads/details.aspx?familyid=0582BC67-0BEF-4A0A-99CF-4408A111C4E3&displaylang=en

Scale Out Poster

http://www.microsoft.com/downloads/details.aspx?familyid=DBBE85C5-4DD4-4B28-B2F1-6197980FD149&displaylang=en

Scale Out Interactive Poster

http://www.microsoft.com/downloads/details.aspx?familyid=D9CC7D13-7324-4F24-88DE-7B063FDE62E8&displaylang=en

Database Infrastructure Poster

http://www.microsoft.com/downloads/details.aspx?familyid=2E322206-03CF-47BA-BDB0-F96770F889ED&displaylang=en

BAM Poster

http://www.microsoft.com/downloads/details.aspx?familyid=193CD7A4-E271-46BB-B4EE-8434DFA779A0&displaylang=en

BizTalk 2009 Hands On Virtual Labs

http://msdn.microsoft.com/en-us/virtuallabs/aa740373.aspx

Infrastructure Planning and Design

http://www.microsoft.com/downloads/details.aspx?familyid=AD3921FB-8224-4681-9064-075FDF042B0C&displaylang=en