The Biztalk exams don't have any official training materials. After trawling through 2 Apress Biztalk books (including Apress Pro Biztalk 2009), all the Microsoft 2009 Virtual Labs and a SoA Book (~1300 pages in total), I sat the exam this afternoon.
As usual, many of the questions are slightly ambiguous and I did a lot of "um-ing" and "ahh-ing" before a decided to click the "Exit Exam" button. Thankfully the numbers went my way. Updated MCP logo including my Biztalk cert will appear soon!