Generating Maps On Your Web Site

Hey everyone, Before attempting my own solution, I was going to inquire if any of you had any slick ways of generating maps on a web site. I would like for users to be able to enter their own address within a listing in a business directory and be able to have a map generated for them, similar to Yahoo Map and Map Quest. I know these map providers offer services at a fee, or services that don't seamlessly integrate with the web page. I was wondering if any of you have a way of generating maps from any of these providers on your own site. Or, is there a service that allows you to seamlessly integrate their maps in your own web pages, preferably not fee based. Thanks a million! Jason