Windows 2003 domain Setup

Hello,

We have office in 2 different location, I would like to setup windows 2003 Domain controller.

We totally have 4 server, 2 servers in each location. Can anyone please suggest me the tree structure and setup procedure in detail please.

Requirements:

Webserver and Active directory

[Webserver – Apache, PHP and Mysql]

I would like to have redundacy for both the server [i.e. if any one server goes down the other server should automatically take over]

We have a VPN connection between the locations.

Thank you very much in advance

Regards
Umesh