Yes, the announcement of the details about the new space X PRIZE, noted here and here on my site, and also on numerous other sites, will be tomorrow (September 13) at the Wired NextFest. I expect to be away from the computer during the announcement, so if you can't wait, check the other space blogs, or any number of other news sources, and I'm sure you'll hear the news before I do. (Yes, I have other responsibilities and interests that have nothing to do with space and/or prizes). I'll post the details when I get a chance, as well as some links to discussions on the news if I find any. Most likely there will be a new link on the right hand side of the Space Prizes blog for it, and a new tag so you can find all my posts on the new prize over time.
Update (Early September 13): NASA Watch has more hints about the prize. Check out the link, and if you're doing it before the announcement, check it again later. Some interesting hints from the NASA Watch post:
"Editor's note: This announcement will knock your socks off. Indeed, paradigms will shift before your eyes. Check in here after 2:00 pm EDT for updates."
"NASA Deputy Administrator Shana Dale will unveil the agency's 50th anniversary logo and participate in an X PRIZE Foundation announcement at WIRED Magazine's NextFest".
As I indicated in those older posts linked at the top of this one, NASA has a large presence at the NextFest. The NASA Watch article (a NASA press release) goes into some detail on their activities there. This quote, though, hints that NASA might be involved with the prize announcement. In what form, though - inspirational only, or as an active participant? The prize sponsor is supposed to be a Fortune 500 company, but there are many roles that NASA could take - Centennial Challenges prize supplementer, supplier of test facilities and data, purchaser of data or future missions based on the prize winner, etc. Of course it all depends on what the prize is in the first place.