The folks at Smashwords, along with various other retailers, are hosting Read an Ebook Week, March 5-11. The promotion began as a way to encourage people to read more ebooks and regard them as books, rather than some inferior media format, but it has the handy side effect of allowing ebook authors to promote their books with discounts.
As a special promotion, you can get the Smashwords version for 99 cents! EPUB, MOBI (Kindle), and browser formats are available. Just enter coupon code RW85W at checkout. Hurry – this coupon expires on Friday, March 13!