Beyoncé is throwing Jay a four-day birthday party, but it's really a wedding," said one source. Guests, including family and close friends, were told to have passport applications filed by last Friday so they can attend the bash on a yacht in St. Barts. But insiders said the guests will also be ferried over to Anguilla for the wedding at Cap Juluca, a five-star resort with Moorish villas. Another spy said Knowles and Jay-Z had toured the site earlier this year and approved it for their nuptials. Reps for Knowles, Jay-Z and Cap Juluca didn't return calls or e-mails.' [PageSix]