Here is a link for windows xp: what os are you on?
http://www.mediacollege.com/computer/network/dns.html
Some of the concepts are very similiar its how you get to the network that might be different. Plus to map to google you need to google what their dns servers are. I also have used opendns.com and their free dns as well. Very nicely done.
Here are their two ip address's:
208.67.222.222
208.67.220.220
Edit: if your on windows 8 or 7 then google "How do i manually configure my dns for windows (x)?" and replace x with what you have and you will get plenty of explanations.
