One of my colleagues, Rick Claus, is currently posting a series on migrating your enterprise from NT4 to Active Directory.

He currently has posted parts 1, 2, and 3 of a 7 part series.

The posts so far:

NT4 to AD In-Place Migration - Are YOU a candidate? (In-Place Migration - Part 1)

How much of an AD design required before a migration? (In-Place Migration - Part 2)

Creating the Lab environment for your AD (In-Place Migration - Part 3)

Expect to see a couple of posts each week for the next couple of weeks.

If you have any comments, head over to Rick's Blog: http://blogs.technet.com/rclaus/