Applying GPOs in a mixed 2000/XP desktop environment

Tech-Archive recommends: Fix windows errors by optimizing your registry

Hi all,
I'm hoping that someone can reccomed a good whitepaper/kb etc that
details the process of managing gpos in a mixed-desktop environment.
Specifically, are different gpos needed for different OS's? Is wmi -
filtering an effective way of applying a gpo (or not applying it) based
on a machine's OS? I'm justnot finding it out there.
Thanks

.