Welcome to iCheers, where everybody knows your whereabouts. Both Apple and Foursquare are offering new tools for iOS5 that will let us know where our friends are at all times. The iPhone’s ‘Find My Friends‘ feature is pervasive tracking of any of your friends (who opt-in), whereas Foursquare’s Radar simply lets you know anytime a friend (who has opted in) comes into your vicinity, whether you have the Foursquare app running or not. You used to need a private investigator to keep track of people this closely. Now you can just install the ‘Find My Friends’ app on your wife’s new iPhone 4s without her knowledge and see if she goes where she said she was going to go on a Saturday night. That’s what one Machead claims to have done this weekend, and now he’s planning to file for a divorce.