J.K. Rowling has started her book tour in the United States (the first since Prisoner of Azkaban) .. to audiences of lucky contest winners (which alas, does not include Wizards Wireless) in Los Angeles, New Orleans and New York. She's been answering questions, doing readings and signing lots of books.
This post at the Leaky Cauldron has pictures, news articles and more. And this post has Rowling's answers to a Q&A session. Be warned, they may contain spoilers.
The Hogwarts Encyclopedia doesn't seem to be in the works anytime soon. Sigh.