Piers Morgan banned Madonna from his American and British shows on Tuesday after initiating a Twitter feud with her. The pop star joined Twitter on Sunday, and Morgan marked the occasion tweeting, "Welcome to Twitter. You're still banned from my show. Love Piers x." Her manager Guy Oseary tweeted back, "Really?" with a letter from the show's producer asking Madonna to be a guest on the British version of his talk show.Read More... More on Madonna