Thank you for doing this howto!
But I find the preliminary information a little too short... One or two network cards? Etch as DHCP server, or external?
I did follow your guidance to the point, and I could not boot clients from PXE. Most likely because a Windows 2003 server handle DHCP, and the scope does not involve the 10 first IP addresses in the subnet (default in the "lazyness" script).