Fair enough. I have great respect for the people who gave us projects like Linux, Wikipedia, etc... I even try to contribute when I can. Even more: I think it is the only model that will protect us from corporate greed (anyone remembers trusted computing?). But there are limits to the free (as in GPL) model, and I really think that location-based services are beyond that limit.
Wikipedia cannot search things near your location, I think (I have not found how). You have to use google for that. Google is... well google.
About a free database for shops, only one word comes to mind: spam.
If you know quite a lot of people who would get excited about a location-based XMMP client, then why don't you start a project?