How can I properly configure the use of OpenDNS?

How can I properly configure the use of OpenDNS?
I’ve configured from IP - DNS - Settings, but barring not working and the way it works is with this rule.
ip firewall nat add chain = dstnat action = dst-nat to-addresses = 208.67.220.220 to-ports = 53 in-interface = Lan dst-port = 53 protocol = udp

The reason why I want to change this way of using it is because that way I do not mark anything on IP - DNS - Cache, and the problem with this is that sometimes use the script to limit some servers downloads such as: rapidshare and megaupload, and nothing since the failure of the DNS cache can not limit.

Thanks … I hope I can help

I use OpenDNS a bit different…

The Router has its DNS set to the OpenDNS IPs…
The Router allows for DNS lookup…
The DHCP scope is set to point the clients to the router for DNS…

Any DNS requests outside the network (IS not using the router) are dropped or re-dirrected to the routers DNS proxy…

Works GREAT Lasts Long time… (I use it for a public hot spot config…)