Google Maps will not be free starting 2012. 4$ per 1k hits, if 25k hits\day exceeded

Google starts monetizing their Maps API in 2012. It will cost 4$ per 1000 hits if your web page with Google Maps on it exceeds 25000 hits a day.

Google Geo Developers Blog: Introduction of usage limits to the Maps API

Alternatives are Bing, MapQuest, OpenStreetMap. Or apply for some "Premier" GMaps license. Or turn into non-profit which will not have such restrictions