Is it against the AdSense policy to do a search with "AdSense for search" on your own site then link to the search results directly. For Example if you have a cell phone site, go to your search box search for "Nokia phone" then link it from your main site to the search result URL so the visitors will not have to search for it they just click on the link? Thanks
No. You are not allowed to pre-populate an 'Adsense for search' search query. The actual visitor will have to use the search box and physically type in what they are searching for, otherwise it would be a ToS violation.