Google launched its own public DNS service today, called Google Public DNS, in an effort to make the Internet faster and safer. DNS, or Domain Name System, is the service that translates hostnames into IP addresses on the Internet. Similar to other public DNS services such as OpenDNS, Google Public DNS will allow Internet users to use these faster and more secure DNS servers instead of the ones provided by their ISP.
Google Public DNS will increase the speed of DNS lookups through caching and prefetching of DNS entries that are about to expire. Since DNS has recently become an attack vector for malicious hackers, Google Public DNS randomizes the case of query names and implements other data in the DNS messages that thwart attackers. Google acknowledges, however, that DNS won’t be completely bullet-proof until DNSSEC is implemented. As far as the privacy of Google Public DNS is concerned, the official policy states, "We built Google Public DNS to make the web faster and to retain as little information about usage as we could, while still being able to detect and fix problems. Google Public DNS does not permanently store personally identifiable information."
So far, there does not seem to be any mention of content filtering capability such as is possible with OpenDNS, but it isn’t inconceivable that these features could be added later. You can use Google Public DNS by setting your DNS servers to 126.96.36.199 and 188.8.131.52. See the Google Public DNS site for more specific instructions. (Sources: Google Public DNS, Google Code Blog, ReadWriteWeb)