Directory Services (Score 1)

It's not "free" but have you checked Apples Leopard server platform? It is easy to manage and can work as a PDC for Win32 machines right out of the box. It integrates with existing domains as a BDC so you can play with it. It has comprehensive directory and service list that makes it a good choice for looking into. Add to that it is a one off cost of less than $1000au for the "unlimited" version.. no CALs to buy for anything.. ever. EB