[CentOS] A good primer to User Administration?

Hi,

I've been running Linux as a workstation OS for years, and have been dealing 
with Windows networks and standalone Linux servers for a while now. 
However, the time has come for me to complete redo the server installation 
and am looking to move to a complete CentOS install base, with only Windows 
workstations.

My question is the following.  I've been searching online for a good 
reference to describe good practices when building a linux network, but 
haven't really been able to find much when it comes to best practices for 
user administration, ACLs, "optimal" (or recommended) file locations, etc. 
For example, I know I need an LDAP server, but not sure how that ties into 
system login, or how to use a Linux LDAP server as the basis for a primary 
domain controller (is it still called that given Windows AD world?), etc. 
Or even how to properly create group structures and ACLs that accurately 
reflect group ownership/etc.  The octal permissions at the file level are 
only good enough for a single group; I need to give multiple groups 
different permissions on the same files, etc.

I realize that there are a lot of questions that I need to research, but I 
was hoping someone could point me in the direction of some advanced admin 
docs with best practices, etc.  Most of the stuff I find relates on how to 
set up a basic standalone PC, without any reference to how to network 
together a bunch of servers running off central authentication, etc...

Thanks for the advice!

Eric