Harry Potter fans, hold on to your broomsticks: After a week of frenzied speculation, J.K. Rowling has revealed that she will release the long-awaited e-books of her mind-bogglingly popular fantasy series through her own e-commerce store and interactive online experience, Pottermore.

Crucially, Rowling will sell the e-books through a proprietary platform, she revealed at a press conference this morning in the Victoria & Albert museum in London. Because of a shrewd arrangement with her publishers Bloomsbury and Scholastic (or possibly just a short-sighted one on the publishers’ side), Rowling retains the digital rights to the seven Harry Potter novels. Bloomsbury and Scholastic still have control of print publishing rights.

Until recently, reports have been speculating that the rights to sell the e-books would be worth as much as $160 million. By retaining the rights and selling them through her own platform, Rowling stands to make much more. She is not, however, completely turning her back on the hands that fed her—her publishers around the world will get a cut of e-book sales and will no doubt benefit from the “halo effect” of an uplift in print sales.

In a further bold move, Rowling has opted to keep the e-books DRM-free, meaning that they are not locked into one device or platform. She is instead opting for digital watermarking that links the identity of the purchaser to the copy of the e-book. This doesn’t prevent copyright theft but does ensure that any copies will be traceable to a particular user. This is similar to how iTunes is DRM-free, but embeds user account information within each file purchased.

In addition to being an e-book store for the seven fantasy novels, Pottermore is also an online immersive experience for which Rowling has written extensive new material (more than 18,000 new words so far) about characters, places and objects in the series. So even if you don’t buy the e-books you can still enjoy the additional content with a printed book or on its own.

“For me, this is such a great way to give something back to Harry Potter fans who made the books such in incredible success,” Rowling said. “I still receive a phenomenal number of letters, drawings and stories from fans. This is way for Harry Potter to live on in a medium that didn’t exist when I started writing the books.”

By publishing on her own website, Rowling adds: “We can guarantee that people everywhere are getting the same experience at the same time. That was extremely appealing to me. I am lucky to have the resources to do it myself and I think this is a fantastic and unique experience that I could afford to take my time over to make this come alive. There was really no way to do it for the fans or me than just do it myself. Not every author could do this, but it’s right for Harry Potter. It is so much fun to have direct content with my fans. It was an extension of the existing jkrowling.com.”

So, what of the new digital world itself?

Developed by digital creative agency TH_NK (in close partnership with Rowling) and sponsored by Sony, Pottermore sets out to entertain and inform readers as they follow the books’ story lines. It is hoped that Pottermore inspires a new generation of readers to engage with the Harry Potter books. The platform features a host of newly commissioned illustrations and interactive gaming elements. When you register, you get to choose a magic user name and then travel through different parts of the book, joining Hogwarts in the virtual world just as Harry does in the books.

In each chapter there are interactive “moments.” In the first book there are 44 of these moments. One such example includes Diagon Alley, where you can enter Gringots (the wizard bank) and pick up 175 galleons — the in-game currency. You can then use this to buy items on your shopping list from shops such as Wiseacre’s Wizarding Equipment.

On the journey to Hogwarts you can explore a virtual train carriage, finding digital trinkets such as magic beans and different spell cards that you can add to your personalized trunk for use later. The trunk can be accessed on your profile page, which shows all of your friends, digital wallet, all of your digital items, details about the wand you have and the house you are in.

The Sorting Hat—which allocates users to a Hogwarts house—is a lot of fun. You go through a series of multiple-choice questions to assess your character. Based on your unique responses, you get allocated a house—Gryffindor, Hufflepuff, Ravenclaw or Slytherin. I volunteered to be sorted into a house in the press conference and got sorted into Gryffindor.

Having been sorted into a house, you can challenge fellow students to wizard duels or by successfully mixing potions in order to win points for your house. This part seems to play a little like a multiplayer game—with leagues of point winners competing against each other.

You can also see what your friends are doing on Pottermore—you can see where they are in the storyline and go and meet them should you so wish.

Rowling took a hands-on approach to Pottermore and came up with questions for the aforementioned Sorting Hat and for the Wand Chooser—which selects the appropriate wand for each user for one of thousands of possible combinations. All of these extra details appear to be the Harry Potter encyclopedia that Rowling has alluded to in the past. TH_NK has previously worked with Sony to create Little Big Map—a huge Google Maps mashup that allows fans of the game Little Big Planet to connect with each other.

Pottermore will be first opened in beta on July 31 (Harry’s birthday) to a million fans, who will be required to find a Magical Quill in an online treasure hunt. They will be able to feed back their comments and criticisms of the site in order to shape the final look and feel of the website before it opens to everyone on Oct. 1. This will also be when the Pottermore shop will open, allowing people to purchase the e-books and digital audiobooks in a selection of languages. The second book, Harry Potter and the Chamber of Secrets, will go live in early 2012. Other books will follow later.

It will be interesting to see what role Sony will play going forward in the strategic partnership—especially how it might work with Sony’s consumer electronic devices such as e-book readers and tablets. One possible shortcoming of the project is the fact that the interactive experience is developed separately from the e-books—but this is likely because the project was launched more than a year and a half ago, before the arrival of the first iPad. However, because it isn’t tethered to a device, it means that it can be enjoyed by readers of the meatspace books as well as the e-books—meaning that the potential audience is much bigger. It will be interesting to see how the Pottermore team comes up with a more seamless interactive e-book experience as opposed to the dual-platform approach.

The fact that the biggest-selling author of the last decade is so publicly committing to the digital space in an industry that has been somewhat dragging its feet is likely to be a significant driver of the e-book and e-book reader industry. The interactive element of Pottermore genuinely paves the way for other authors and creative teams to think beyond the realms of the printed page when it comes to devising e-books. Despite the fact that the books were written years ago, it doesn’t feel like a tagged-on experience—Rowling and the team at TH_NK have taken great pains to ensure that the environment is visually stimulating, authentic, playful and utterly complementary to the stories.

See Wired UK’s gallery of Pottermore images.