In the past, when a user on your site would use AdSense for Search they would end up being taken away from your site to see the search results.
Google has changed it so that you can now generate search results within your own site. They will be shown in an iframe.
Google has instructions on how you can implement AdSense for Search results into your own page. Here is a link to those instructions
https://www.google.com/support/adsen...y?answer=43862