Infact placing Google Ads in your site is really simple. For that matter you need to have a google account. Once you get a google account goto www.google.com/adsense and login with ur user name and then apply for an adsense account. Google will then verify your site credibility and based on that they will approve or deny your request.Once they approve you can sighn in to www.google.com/adsense and log in with ur user id. After logging in they will provide you with an easy step by step instruction and finally you will get a code snippet which will be a piece of Javascript. You can place this code in your website and thats it, done.

Hi,

just paste the google html code into the actual aspx masterpage wherever you want it to be shown,

JC

Hi,

Paste the code in some column of a table.

Placing ads in your pages is upto you. you can place it wherever you want it to be.
infact you can put a horizontal banner in your footer that repeats in all your pages.This will resolve the headache of putting the same ad in all pages.
Master pages can have header and footer right?so u can add this in the footer section.