Google Public DNS is a DNS service by Google like OpenDNS, harnessing Google's crawling technology where Google has had to perform thousands of DNS lookups. It is free. Google built it on the policy that it is fast, secure and reliable. Google uses anycast routing to direct the user to their nearest Google datacenter in order to make it fast, they hardened it for security and it gives the best exact answer it gets from DNS servers (no redirections, for example), making it reliable.
Setup for Google Public DNS is easy: you can make your router use it or your local computer use it. The nameserver's IPs are:
For IPv6 they are: