[Samba] howto "upgrade/transfer" samba domain-user + domain-group data to a new windows 2003 active directory domain?

[Urs Rau]

I much regret in many ways having to ask this question below. But our
business needs now demand more than we think we can deliver using open
source software exclusively.

What is the best way to 'suck up' all of the domain group and user
data from a current samba 3.0.21a PDC into a microsoft windows 2003
server?

We have two basic needs that demand we now introduce active directory
servers to our previously 'windows server free' office. One we want to
manage the windows xp sp2 desktops using group policies and secondly
we have a need to start using shared calendaring.

Alternatively, I would also welcome any suggestions that would allow
us to use microsoft outlook shared calendaring and enable us to manage
the windows xp workstations using group  policies, using any other
configuration, preferably open source of course. ;-)

Many thanks in advance for any hints or suggestions.

PS: Please note there is _no_ active directory already deployed. All
of the user and group info is currently on our samba 3.0.21a PDC
running on a CentOs 4.x box.

-- 
Urs Rau