Friday March 25, 2005 10:00 PM ET Britney Spears and her husband of seven months, Kevin Federline, are expecting a baby, Star can exclusively and definitively reveal! The 23-year-old singer is three-months pregnant, according to sources close to the couple, and an official announcement confirming the happy news is expected to be released this weekend. Sources say Britney has canceled all her future work engagements and is busy preparing for her new job - motherhood - when the baby arrives this fall. Brit's made no secret of her desire to start a family since her marriage to Kevin Federline on...