I bought it this morning through the iBookstore and can't wait to read it.
It seems the prices for the ebook versions have been all over the place today. This morning Amazon had it for US$9.99 and right now it's at US$10.36. Not a big difference, just weird.
What's really strange is that the US iBookstore is selling it for US$16.99 while the Australian one is selling it for AU$9.99. I can't complain about that, but it's just really weird. Normally the Australian store has all prices about 30% higher than the US store.