First time a site that loading slow for you. This site is suggested to test since it loads slow. Sports Illustrated: http://www.si.com You should instantly know if things have improved when visiting that site. (note: loads in under 3 seconds for me)
Download and run: Namebench (free) http://code.google.com/p/namebench/
Once you have the fastest domain name servers, you then have to manually change your DNS settings in System Preferences/Network/
Select different browsers under the popup. I got variying results when using different browsers. Surprisingly, Firefox suggest Google Public DNS as primary, but Chome and Safri gave me same settings.
System Preferences > Network > Select you internet service (be it Airport, Ethernet etc) then click advanced tab > Select DNS and enter the settings
BTW, Google server settings are- 8.8.8.8
Another option is to try turning off IPv6:
In System Preferences --> Network -> choose the Ethernet tab in the far left column --> Advanced button -> TCP/IP tab --> Configure IPv6: dropdown menu, choose Off --> Okay button.
The reason that turning IPv6 off may improve performance is that some DNS servers do not properly respond to IPv6 requests. As a result, your computer has to time out waiting for a response and then try a secondary DNS server.
In recent versions of OS X, IPv6 typically is set to "automatic" by default. You have nothing to lose by turning IPv6 to "off" and then seeing if performance improves.
Hope this helps!