Spoiler:
The man at the beginning is a commentator for the Blitzball game, he's just talking about how it had been 10 years since Jecht went missing. He's basically like Jimma and Bobba, the two commentators at the Luca Blitzball tournament.

The clip of Tidus smiling after the credits is a sneak peak for the "Good Ending" in FFX-2.