What you're asking isn't impossible... in fact its not that difficult. Since you are installing it in a remote location, there are some considerations involved concerning the bandwidth between the branch and central location. If it was me, I would have the second domain controller running with active directory integrated DNS, DHCP, WINS, also have it set as a global catalog, and have it set in it's own site in sites and services to manage replication of active directory and other services between sites. The structure of what you are doing falls under the category of Wide Area Network. Your second Domain Controller is not going to be connected to your central location with a nice fast 100mb or better connection.
There is alot of information and the best way for you to access it is windows help (I'm not going to publish all that here). Adding a second domain controller to the domain is extremely simple. Windows help covers this too. But you really, really need to look into sites and services once you have that DC up and running. Unless you control the bandwidth and timing that active directory, DNS, WINS, and other server services are using to replicate information across the WAN, your users are going to complain about the network being slow. You also want to provide quick access to domain resources like name resolution and logging in... this is where having DNS, WINS, and global catalog located at the branch office is a big advantage.
Yes, the help is big and alot of reading, but EVERYTHING you ever wanted to know is in it.
