I have a fairly large site that runs across 2 cpanel servers. To spread the load when I first went to a second server I created the forums as a subdomain and pointed the subdomain a record on server 1 to server 2's IP...

Server1 = www.mysite.com
Server2 = forums.mysite.com

The thing is I have seperate name servers on both servers, but the mysite.com domain is only pointing to the first server. This means if server 1 goes down then nobody can access the second server. Can I just create a DNS zone on server 2 that exactly matches the dns zone on server1 and then add server 2's dns servers to my domain as the 3rd and 4th name servers?

If I understand you correctly, you need to make one hostname pointing to both IP addresses.

is the site on each exactly the same? is it a static site?