Converting a MS company to Linux

[Scott Henderson]

As some of you know, I'm the senior administrator at a company
that runs MS on all of its servers and clients (well, we also
have an AS400 system, but I'm not involved with that). We use
Exchange for mail, Terminal Server, Windows file sharing, etc. A
standard MS house.  I've managed to spark interest in Open Source
solutions among a previously die-hard MS-focused group of admins
(and the shirts and ties above) by setting up a Red Hat server
with spam-filtering software.  Suddenly I'm in the rather
exciting position of being given [almost] free reign to research
other Open Source solutions, including things like Communigate
Pro as an Exchange replacement (groupware version in beta), LTSP
as a Terminal Server replacement, and various Linux distros for
desktop use (Mandrake with ICE is in the lead :).  I've not been
given a budget to bring in consultants, but I can work on it on
my own.  There's a world of opportunity here, but the scope of
this is a bit beyond my year and a half of experience with Linux.

I need to quickly get a decent grasp of the possibilites for
moving us away from a MS-based, Active Directory network.  Is
someone with Linux sys admin experience, especially migrating
from MS systems, willing to spend a little time with me on the
phone or exchanging emails to discuss this?  I think it's too
much for this mailing list, but I don't require hours and hours
of time, either.  I'm not looking for someone to hand everything
to me on a silver platter.  I can figure out much on my own, but
would appreciate some one to fire off questions against on best
practices, etc. 

And/Or... suggestions for mailing lists or other resources?

Thanks,

Scott