Great idea! Some feedback from me.

1) When I type in the city name in the search box, I can hit return to make selection, I have to click on the city in the drop down menu.

2) missing search box on the front page.

3)I type in France, and it says nothing matched my search. I would have expected that Paris would be shown.

4) I like that you are using OpenStreetMap instead of Google's or Microsoft's map products.