Fans will get a glimpse of new material from Pottermore tomorrow, the team behind J.K. Rowling's website just announced.

Coming up tomorrow: the first of three special previews of one of the Pottermore chapters, Pottermore tweeted a short time ago.

Here is a timeline of things to come on Pottermore:

* On July 31, Harry's birthday, will come an online challenge in which the first million people who register will be able to see the site early and help put final touches to the experience -- if you speak English, French, German, Italian, and Castilian Spanish.

* The site opens to all in October, when users can begin traveling through book 1, Harry Potter and the Philosopher's (Sorcerer's) Stone.

Readers will move through the chapters, getting to join Hogwarts (like the boy wizard), get sorted into a house, and make potions, while seeing new writing from Rowling, according to Pottermore.

* Also in October, as the site is finally launched, the Pottermore Shop will open. It will notably sell the Harry Potter e-books for the first time, as well as digital audiobooks.

* Early in 2012, the interactive storyline of book 2, Harry Potter and the Chamber of Secrets, will be added to the site, with subsequent stories to be unveiled over time, according to the website.