Dropdown Categories Listing in search results

Hi,

Can you advise how I can add a Categories drop down into the search results page. I have been changing the search.php file to make the results a little nicer, however I would also like the users to be able to select a category at the top of the page if the results do not provide them what they need.

I added a small bit of php code into the search.php result which sort of worked, but there was no structure / order to it and it did not pull up any counts etc, so it must be able to be done, but not the way I have been doing it.

Thank you,

Paul