We have setup a new domain (Windows 2008) that is not on the same forest as the rest of our 2003 domain. With this new domain, comes 2008 DNS server (of-course). We were able to add a forward lookup zone (2ndary) of our 2003 domain from our 2008 DNS server but we can't create a forward lookup zone for our new 2008 domain (on a different forest) from our 2003 DNS server.
There are no trust relationship establish at this point. We don't want our 2008 domain to access resources or anything in our 2003 domain.