Ember for iOS will be a free Universal app requiring iOS 7. In the coming months, we’ll be adding annotations and other features as In-App Purchases, however the ability to view and organise your Ember library will always be available for free.
I'm using Ember as a digital scratch book for all my non-personal images. I collect sketches, screenshots, movie posters, doodles etc in it. It's a great app, but I often missed the option to save items I discover on my iPad to my library. Apparently that issue will soon be resolved.
Available in December.