In my site iam using GMaps API Javascript with PHP & MySql. It can detect users country & set home page layout & information related to that Country. Presently this can search any Place Names over the World ( I have Mysql Database which have more than 8 Million Place Names) & find Road directions of Any Country. Also there is a option for users to add & display their interesting Places into POI ( Points of Interesting) Menu, country wise. If someone interesting this kind of web application submit your ideas. Then I can help you.
Very cool - you should add a social media aspect to it / location-based data. I'd say use the foursquare API and the regular API as well as possibly flickr and other sites? Adding augmented reality data to it and syndicating your data to layar for example would be pretty cool
Thanking you iMarketingGuru for your suggestions! Now It is contain Panorama Photos & Wiki Articles. Now Iam try to add You tube & Flicker Contents .