I just found this great document on the Microsoft site. I've been looking for material to help plan BTS projects and from the first glance it would appear that this is a good source. It was written in Oct 2003 and intended for use with BTS 2002, but im sure the concepts would remain the same.
According to the blurb
"In this book, we'll take a look at what you will need to start a B2B integration project with BizTalk Server, as well as how to proceed to the other stages of the project. In particular, we will take a close look at the Microsoft Solutions Framework (MSF), which provides proven practices for planning, building, and deploying successful EAI and B2B integration projects with BizTalk Server."
Hope you find it useful to. By the way, I also recieved the "BTS 2004 Unleashed " book from Amazon and am highly excited about it. Going to start reading it right away.
Cheers
Benjy