Linux replacement for Microsoft Server 2003 AD/ Exchange 2003

I am deployed with the 101st Airborne (AA) to Iraq, and I have been tasked with setting up a network capable of withstanding abuse of the Iraqi Army. This quite a task since the US Army is ATTACHED to using Microsoft products. I know that the best choice in accomplishing this task is to use a distro of linux. I have chosen ubuntu since I havn't had problems with it in the past, and it has great support for arabic (which is another salty nut roll) The problem that I have now is being able to setup an AD type server so that I can manage accounts, run an email server for these guys, and I'm sure that they will need file sharing and all that funny stuff. I have a copy of ubuntu server. I need to know how to setup a domain, setup an email server, and setup a login type system so that I can manage their accounts. I also need to know if there is a gui interface that I can use to manage it. It'll be for them to use once im gone.


Thanks for any help in advance

SPC Seth Alton
1-502 Commo
101st Airborne (AA)