You'll probably want to visit/consider more than just the public preschools. Two sources for names/phones of local private preschools - the public library and naeyc.org
the second one is national assoc. for the education of young children - they do accreditatation of preschools. even if you don't end up in a naeyc accredited school, their website has great resources for questions to ask and things to look for. most important - go w/your gut. What's great for one family may be horrible for yours and vice versa - kids have such different needs!