Seems pretty straight forward.
Under category: Choose your topic.
Under sub category: refine your search.
Under Search engine: find it on your favorite search engine.
Nice idea. I hope it works out for you. However, you might want to get some design tips in the Review My Site Forum. Take a look at the [forum guidelines there ([URL="http://www.sitepoint.com/forums/showthread.php?871218-Need-a-Web-Content-Review"]they are also stickied in this forum](http://www.sitepoint.com/forums/showthread.php?744418-Read-before-requesting-a-review)), follow the directions and see what the community thinks.
By the way: Welcome to SitePoint!