It's a horn. It's typical of South African soccer games. It's expeted in a Sotuh African game. The organizers knew about the vuvuzelas, they're stupid, annyoing, and retarded, but I honestly think it's not that big of an issue, at least as a viewer.

Now if it's affecting gameplay, fine. But frankly, I think it's almost as bull as the "ball curves" excuse. Stadiums are loud. With or without vuvuzelas.

EDIT: No, the vuvuzela is not the pride of South Africa, but if by "playing" it shows the elations of hosting the World Cup, I wouldn't at all call it selfish.