Good update on PaidContent.org on the state of publishing and the impact of e-books for 2011. It looks like e-book revenues were up 117.3% in 2011 with hardcover, paperback and mass market sales declining. This is a trend that I believe will continue. One point I have though on this is that while the declining gets a huge amount of attention and e-books look like where the world is going there are still a lot of physical books being sold. So in your publishing efforts don't forget that you should be doing both.
Link here to read the full article on PaidContent.org http://paidcontent.org/article/419-new-stats-2011-was-good-for-e-books-not-so-good-for-print/#keep_reading