2 different networks at the same time?

Here's my situation. I have 2 wireless routers, one connected to the internet, the other isn't (for a controlled learning area). I have 2 wireless NICs that work perfectly without a problem and I can connect to the 2 networks, but then I have an issue with DNS lookup issues when I am trying to browse the internet on my internet enabled network. The reason I am doing this is because I want to thoroughly read through Metasploit Unleashed and other resources of the like while trying the new tools on my controlled network; switching between the networks every time I want to view the next webpage is a hassle. If this isn't possible just let me know and I'll put the controlled area online and work with it that way, I am just curious if it's possible to not do that. Thank you for any help.

This has nothing to do with backtrack, but rather basic networking skills.
The only problem I see here is that your internet connected network can't find an appropriate DNS server. It would be a good idea to find out what the router thinksiis the gateway and ensuring that this is correct. Generally for a home user type scenario, the gateway is the public facing IP address assigned by your ISP.
Accessing both networks is a trivial matter of ensuring that the responsible router has the gateway's in it's tables for both networks, the client (NIC) tries to access.