Will This Work?

[phuckedup]

never mind, it will ;)

[CareBear]

To do this, i want to mix the nameservers so when it can't find the subdomain on server 1, it will find it on server 2.I don't entirely understand what you want to do :confused4
Do you want a rule that's set to "whatever isn't hosted on server 1, should automatically be handled by server 2, regardless of that fact whether I told it go to server 2 or not"?

If you want some basic level of redundancy, one way that should work with most hosts is:
yourdomain.com
nameserver 1: ns.server1.com
nameserver 2: ns.server2.com

If you want domain.com, www.domain.com (http://www.domain.com) to be handled by server1, but forums.domain.com to be handled by server 2 for example, you'll need to make sure that ns.server1.com has an A record for domain.com and www.domain.com (http://www.domain.com) pointing to the IP of server1 and an A record for forums.domain.com that points to server 2.

ns.server2.com should have an A record that points to the IP of server 2 for domain.com, www.domain.com (http://www.domain.com) and forums.domain.com.

If server1 is up and running all DNS lookup requests will go through ns.server1.com, so (www.)domain.com (http://www.)domain.com) will be handled by it and forums.domain.com will be handled by server2.
If server1 is down, clients will try to contact ns.server1.com but fail so next in line is ns.server2.com which will then serve all three subdomains itself.

Do note that this isn't foolproof since both the visitor's OS and their ISP will cache the DNS lookup. Depending on your host that can expire in 1-24 hour(s). Until the lookup expires from either cache they'll still try to contact server1 regardless on whether it's down or not.
In reverse, if server1 is down and www.domain.com (http://www.domain.com) resolves to the IP of server2, visitors will keep contacting server2 for (www.)domain.com (http://www.)domain.com) even if server1 comes back online unless the lookup expires.

The way you'd do it if you wanted real redundancy is to direct all DNS lookup to a server (that's guarenteed to always be there), which will then dynamically keep track of server1's status. If server1 goes down, it redirects to server2, if server1 comes back up, it will redirect back to it without having to worry about cached DNS lookups.

[phuckedup]

thanks carebear, i figured it out (had an idea of what had to be done) but this has cleared it up a bit more. If only i edited my post a few mins earlier, i wouldn't have wasted your time typing all that :P but thanks again