Durn. I was really looking forward to the Battle of the E-readers, with the Amazon Kindle and Barnes & Noble nook confronting the newest challenger on the evolutionary ladder: Apple's full-color, multi-function iPad, which comes out April 3. But Amazon showed off an interesting flanking maneuver this week, releasing some details of its Kindle app for the iPad and other tablet computers. The app -- which is similar to the iPhone app but still being refined -- circumvents Apple's digital bookstore, allowing users to buy from Amazon while using an iPad or other tablet. As Amazon's promotional page says: "Get the best reading experience available on your tablet computer including the iPad. No Kindle required."