Google AdSense is a contextual advertising program that helps you monetize your website by showing ads related to your site's content. In order to place AdSense ads on your site, you first need to visit the AdSense website and generate an AdSense code, which gets pasted into your website's HTML code. You can learn how to obtain your AdSense ad code in just a few steps.
Instructions:
1) Visit the Google AdSense website at Google.com/AdSense and sign in with your Google account information.
2) Click on the "My ads" tab at the top of the page.
3) Select the "+New ad unit" button near the top of the page.
4) Design and configure your ad using the options on the "Create new ad unit" page. When finished, click the "Save and get code" button at the bottom of the screen. Your AdSense code will be displayed on the next page.
Source - eHow
