Instagram is a nice service which is available for iPhone and Android. It allows you to take photos then apply filters to it and then you can upload those photos to web app. Currently its only available for iPhone and Android.
Many times we want to search or find some photos on Instagram by filtering location but there is no option by default to view it. But Worldc.am is a nice online web app which allows you to search for Instagram photos on the basis of location.
This web app is built using the APIs from Instagram, Foursquare,Geonames and Geoplugin which lets you search for photos across the world very easily. Once your search and if it find photo then it will display photo and shows a Foursquare map too.