CLEAR LAKE, Iowa: As thousands of people cheered along the Fourth of July parade route here, it was the tall man with the familiar white hair who made the crowd go truly gaga. "Bob Barker! It's Bob Barker!" two women shrieked upon seeing the former president, Bill Clinton, in the distance, as he and Senator Hillary Rodham Clinton of New York marched hand-in-hand. When the women realized who it really was, they seemed just as thrilled, shouting, "Ohhhh!" and clapping madly.