Foursquare has updated its location-based social networking app for the iPhone and iPod touch, adding basic support for iOS 4 Fast App Switching and high-resolution artwork for the iPhone 4 Retina Display. The update also adds an integrated map view allowing users to view their friends’ check-in locations displayed on a map relative to their own position. Although Foursquare can now take advantage of Fast App Switching on capable devices it does not yet provide other iOS 4 multitasking features such as background location. The latest version continues to support optional push notifications for tracking friends’ check-ins. Foursquare 1.9 is ”>available from the App Store as a free download.