Amazon's Whispersync service has made it easy for readers to quickly switch back and forth between an ebook and an audiobook for a couple years now, letting owners of both pick up either copy at the exact spot where they left off, and now Amazon's making the feature even more seamless. With an update to the iOS and Android Kindle apps today, it'll be possible to make the switch between ebook and audiobook right inside of the app, rather than having to jump from the Kindle app over to the Audible audiobook app, as was previously necessary.