How to join existing 2003 servers to a new 2008 domain

Hi... Hope you can point me in the right direction on this... I currently have 3 locations connected via VPN and each location has a 2003 R2 server. These servers are not in the same domain, each server is its own Domain. I am connecting another location to the VPN and that new location will have a brand new 2008 R2 (64) server (not yet configured). I would like to consolidate these multiple domains into a single domain, having the 2008 R2 be the DC of the new domain and the existing 2003 R2 be members of this new domain. I want all servers to replicate AD in order to authenticate users if a VPN link to the main server goes down.

What would be the best way to accomplish this?

I have looked around for a post on this specific scenario but most of them are relating to either adding a 2008 to a 2003 domain or upgrading 2003 to 2008.

Your assistance would be greatly appreciated... Thank you in advanced!

In the case of the combination of fully qualified domain name, you do not receive an adequate response binding to pings sent to the LDAP domain controllers in the beginning of the process of combining domain. The helper domain controller responds, but the client consider joining the incomplete response. After receiving the same answers to all domain controllers located using DNS, returns to perform a NetBIOS name query for the FQDN domain name to try to locate a domain controller, however, this does not get a response combined operation. In the case of the hypothesis that the client sends a NetBIOS NetLogonSamRequest all domain controllers receive the query WINS for the domain name. However, not being treated properly and produces the second error.