Designing a Directory Services Infrastructure (Exam 70-219)

Make sure you check what is probably the best Dave's Notes I've written to date.

The Cramsession Study Guide for this exam is not as helpful as their other study guides, but the second half has some good stuff (prints out at about 9 pages).  It does require a log in, but worth the effort.

The official Microsoft Preparation Guide outlines the skills being measured.