Move over, Kobo -- following the promise of a Summer launch, Amazon's Kindle app for Android is now live, bringing the usual array of features that existing Kindle users will hold near and dear: access to the Kindle store right from the app, adjustable font sizes, free book samples, and most importantly, wireless bookmark synchronization with your entire stable of Kindle-equipped devices (because we know you've all got an iPad, iPhone, and physical Kindle lying around somewhere). The app requires Android 1.6 to operate, which is going to leave a few people in the lurch -- but it's always good to have a compelling reason to upgrade hardware, is it not?