Hi
Please visit this link (http://book.itzero.com/read/microsoft/0505/Sams.Microsoft.BizTalk.Server.2004.Unleashed.Nov.2004.eBook-LiB_html/) here you can find free online book on Biztalk server 2004. This book contains step by step process and really help to learn Biztalk 2006 for beginners.
Regards
Raman Tayal
My blog: – http://ramantayal.blogspot.com