Many companies change their DNS server to the trusted DNS providers to increase their speed and security and it also works in manyother ways . Thats why inorder to provide this facility to common internet users i am making this post, Therefore, i would refer Google to you for changing your Dns server. It's fully trusted.

ADVANTAGES:
1) It let's you surf web with more speed than your common DNS server.
                                     2) It is more protective and secure
                                     3) Gives url typo correction
                                     4) Gives url shortcuts

How to Change DNS:

Change your Dns server settings to this
8.8.8.8
8.8.4.4

Changing DNS settings in Windows Xp:

Goto Control panel > Network connections
select your connection,
Click properties then select internet protocol(TCP/IP)
Then,
Click properties. A window will pop-out like this


Change Dns Server to the opendns's server,i-e 8.8.8.8 and click okay and you are done.

Changing DNS settings In Windows 7:

Goto Control pannel > Network and sharing center then click
Change Adapter Settings.



A window showing your connections will pop-out now right click your active connection and goto properties like this: