Greg Kinnear, who stars (as the smug boyfriend) in the new movie “You’ve Got Mail” with Meg Ryan and Tom Hanks, is enjoying his success on the silver screen. But he tells the upcoming issue of USA Weekend magazine that he’s a little apprehensive about stardom. “Being out with Harrison (Ford) or Jack (Nicholson), seeing the public constantly wanting a piece of them — there’s a side of that that’s really scary,” Kinnear said. One thing that doesn’t frighten Kinnear is fatherhood. He plans to marry longtime girlfriend Helen Labdon sometime next year, and Kinnear says they plan to have a family. “I say 16 (kids). Helen says two. So we’re just trying to work that out.”