I just checked Barnes & Noble, and The Sixth Discipline is now free in the Nook store! That means Nook came in second to iBooks in the race to match the Smashwords price change. Also, it means you can make a book free on Nook if you use Smashwords to publish. You cannot do that via the Pub-It platform, which, like KDP, sets 99¢ as the lowest level price authors can charge.
Any Nook users out there, head on over and pick it up now!