Question : Extending the domain to remote sites

We have a domain in our main site, the domain consists of two 2008 active directory servers + DNS.
We would now like to add redundancy domain controllers on two remote sites to extend the domain.
How would this be best executed;
Thanks

Answer : Extending the domain to remote sites

You can check out this answer here :

http://www.experts-exchange.com/OS/Microsoft_Operating_Systems/Server/2003_Server/Q_23713714.html

http://www.experts-exchange.com/Software/Server_Software/File_Servers/Active_Directory/Q_23813529.html

and these tech net articles :

http://technet.microsoft.com/en-us/library/cc783262.aspx
http://technet.microsoft.com/en-us/library/cc754920.aspx
http://technet.microsoft.com/en-us/library/cc732632.aspx