SetDNS is the easiest way to force your rooted phone to use custom nameservers on WiFi for all devices AND 3G/mobile networks on rooted devices. Works for both IPv4 and IPv6 networks and nameservers. Please don't install on android 4. 3 for the moment, there are problems with the way dns handling has been changed in the kernel. I've pulled it from the market for 4. 3 devices.