These instructions are currently for the Buffalo Airstation.
1. Visit the router's IP address (http://192.168.11.1) in a new browser window.
The prompt "Enter username/password" screen will appear. By default, the username is root and the password should be left blank. If you have changed the defaults, then enter your corresponding information.
If you have forgotten your password, you may reset the router by pressing and holding for a few seconds the reset button located on the router itself.
Please write down your current DNS settings before switching to OpenDNS, in case you want to return to your old settings for any reason.
The addresses for Open DNS are:
Instructions courtesy of Zach Marshall