The info and the purchase url is here: http://ffxiv-fanfest.com/na/blog/ind...st-blog-8-1619

According to the site you have until august 31st to make the purchase. Make sure to note what dracklor said, you only get one minion (a specific minion is designated for each stream, Rikku is for the vegas stream) and enough vouchers for one of the two full outfits per stream. You'll be forking over $30 for each stream.