I took the BizTalk 2004 exam today and passed. I thought it was pretty hard, but the questions were fair, and a good test of your hands-on experience and understanding of the product. It would be hard to just cram for the exam from documents, if you don’t know the product, you won’t do too well. It has a reputation for not being an easy exam, so that’s more credit to anyone who passes.
Some resources I found helpful:
BizTalk Server 2004 Unleashed
Good info in the more detailed sections, and helpful for the admin, and management stuff.
BizTalk Documentation
Read the more advanced stuff (and make sure you have the latest update!)
SDK Samples
Run through these, deploy them, and get an understanding of how the code works.
Deep Dive Course
If you have a chance to get on the course, go for it, it’s a great help for the exam. If you have taken the course and understand the content you have a good chance, re-read the slides on the stuff you are unsure of.
Whitepapers
There’s a good section of whitepapers appearing on MSDN, they are worth checking out.