Hello. :) You can now refer advertisers' sites in Google AdSense. In addition to being an affiliate for Google products and services such as Firefox and Google AdWords, you may now pick advertisements you would like to refer to others who visit your website. This is still in Beta stage so you have to apply for it.
Get more info from the source here:
http://www.google.com/ads/adsense/re...tm_medium=blog
Good luck! :D