Pottermore is a website that will build an online experience around the reading of the Harry Potter books.
Pottermore seems like it will be a place to share all things harry potter; like fanfiction, art, maybe even costumes. JK Rowling will even be participating in Pottermore, giving us more info about Harry Potter that she's says she's "been hoarding for years".
Pottermore will be open to everyone in October, but on July 31st, Rowlings and Potters birthday, a select few will be chosen to experience Pottermore Early. Im guessing it's going to be maybe a trial group to help shape it. To try and gain early access, go to Pottermore and enter your email address. Good Luck!