Google accounced their public DNS . They claimed that the DNS will speed up the browsing and improve the security. To using google Public DNS, you must change your DNS setting that usually automatically provided by your ISP with Google DNS IPs :

• 8.8.8.8
• 8.8.4.4

I will not teach you how to change your DNS setting, I think that you all understand how to change DNS setting for your connection, or if you have problem, you can see this video :

Google Public DNS and Privacy :

Google claimed that their Public DNS will secure your privacy, it’s real? Quoted from pcworld.com :

• Your IP address: yes. But only temporarily. That data, Google says, is never stored for more than 24 to 48 hours, and it’s collected solely to identify technical problems and help protect from attacks.
• Your name or other personally identifying information: no. Google assures this type of data is never collected.
• Your location: yes. Google says it permanently stores “metro-level” info on your whereabouts for the purpose of debugging and improving the Google Public DNS experience. Most of this information is held for two weeks, Google says, though a “small subset” is sampled for permanent storage. The company promises that it never ties the location data to any other information collected from your session.
• The Web sites you look up: yes. But again, Google says that information is not stored along with any data that would identify who you are.
• Lots of technical details: yes. Google Public DNS permanently logs technical items such as your request type, transport protocol, and the length of time it takes the system to complete your requests. You can see a full list of these technical details on Google’s official Public DNS privacy policy.

None of the information collected, Google says, is ever tied to your Google account, stored as part of your profile on any other Google service, or shared with any third-party provider.

Tips : Before you decide to using Google DNS  for your main DNS, please compare the speed with your existing DNS. If your existing DNS more faster than Google DNS, why you must change to Google DNS?