I recently placed the "AdSense for search" on my site and then I went to search "MY SITE" through my site and it came up with no results found... is there a certain amount of time that it takes before it is able to search your site? Thanks
The search features basically queries the main Google index. If your site has been indexed and is in the SERPs, it'll show up. If not, then, no.
You have to optimize your site in order to get half way good results for searching your site. I dropped this feature. It wasn't worth it for me. There are better solutions.