Our main HQ has two DC's with DNS running on Windows 2003 SP2. We added a remote site so I took a member server at the remote site (linked to the main site using hardware VPN) and ran dcpromo on it and it upgraded it to a domain controller. But I realized it did not install a DNS server nor did it ask me to. Thinking I missed the DNS setup step I demoted the server and manually installed DNS server role and promoted the server to domain controller. Now going into the DNS I don't see the domain zone listed and I don't also the _msdcs zone there either. Do I need to manually add a zone?
The DNS zone is configured by default (although I guess you can reconfigure it differently) to replicate to all DCs in a domain. DC replication is also set by default to replicate across sites every 3 hours. Practice patience and you'll notice the DNS zone automagically appear. If it's not, run dcdiag, check your DNS settings on the new DC, and make sure a DNS record was created properly for the new DC on the old DC.
Are your AD DNS zones AD integrated? If so, then as Jason stated you'll just need to wait for intersite replication to replicate the zones to the new DC.
You should also make sure:
That the new DC\DNS server points to itself for primary DNS
You have Active Directory Sites & Services set up appropriately for each site and subnet
That the new DC\DNS server is also a Global Catalog server
That clients in the remote site point to the new DC\DNS for primary DNS