URL rewrite

Hello Experts, I have a query on URL rewriting. I have a site, which has categories and products under the categories. the url has been re-written to hide the .php part of the pages, the page also shows up correctly when we do type in the .php extension. this is how a link shows : eg : localhost/showproducts?category=fantasy&book=A Game of Thrones I was thinking of getting the url re-written to localhost/fantasy/A Game of Thrones I think this shows a cleaner URL and could be better for the SEO too? any help is appreciated. Thanks, Vinay