I want to remove the query string in the url

Hi,
I have been using this plugin and it works gr8 on many of my websites. On one of sites, I have created a custom post by name preschool. Whenever I add a new preschool, I get query ? in the URL. I have read that this bad for SEO. Can you let me know how I can remove this. Example , http://indianplayschools.com/?preschool=bachpan-balaghat-waraseoni. I want this URL to be without ? and = . Please help me change all the further preschool urls created and redirect the existing preschools .