Ok all, I've been working on Netware Client/Zenworks integration in my spare time and have found the following assuming you are using IDM to replicate eDir users and groups to AD:
1) join XP desktop to an AD domain - this is a must. VDM SSO does not seem to work without being in the same domain as the user logging into the VDM Client interface.
2) install NWclient 4.9 or above
3) configure contextless login per http://support.novell.com/techcenter/articles/ana20030901.html
4) install vdm agent
5) entitle user to desktop/pool
6) user logs into VDM client or web interface and provides username, password, domain.
This will sso into the VDM desktop including desktops in pools.
The only thing I didn't get confirmed was the contextless login as I only had the only DLL based contextless login, not the one referenced in the URL above. Can someone test and confirm this as I will not have access to an environment to test for at least a month. Not that you've been waiting long 
The only thing that does not work, is Zenworks computer policies, but user policies do work.
An alternative approach is:
1) install NWclient 4.9 or above
2) configure contextless login per http://support.novell.com/techcenter/articles/ana20030901.html
3) install vdm agent
4) create generic user with no rights to anything, not even Domain Users?
5) entitle generic user to desktop/pool
6) change VDM Client shortcut to use command line with generic user, password, domain, desktop name etc or put that info in a file and reference the file with -file xxxxx with xxxxx being fullpath\filename.ext
An alternative to this item is not install the SSO component in item 3. But the user must login twice.
7) user runs VDM Client and autoconnects and is presented with NWClient login dialogue box, everything works as expected
This still gives us centrally managed dynamic desktop pools, just not so dynamic connection.
Hope this helps
Phil
