"CCL4s provides an interface for entering observation data as well as access to all the Content Standards for Mathematics K-12 and the ISTE NETS.S. The collected observation data can be shared via email or with our unique built-in instant meeting. The graphs are very interactive and allow observers to merge different observations to compare and contrast different teachers or the same teacher over time. Using the Timeline feature, observers can track the observed Look-fors through time."
This app is free until April, though know that some content becomes an in-app purchase. Bookabi allows students to create their own storybooks with 2D and 3D characters. They can upload their own photos and pictures plus save and share their final projects.
For any student interested in Astronomy, this is a very cool app. It is also a great experience with augmented reality and could be used as a way to spark ideas about other content as well.
With Pocket, it's possible to curate content to read offline or online. It has similar features as Diigo, but uses a visual interface similar to Flipboard. Definite potential here.
If you are looking for a way to read lots of blogs and web sites from your iPad or iPhone, Google Currents could help. It is an RSS reader that saves content for off-line reading.
Lately, we have been discussing using QR Codes to help manage workflow for disseminating content to be accessed on iPads. This is another great post from Richard Byrne, with an embedded Common Craft video, explaining ideas for QR Codes in the classroom.