Technology Integration Matrix with video examples for every topic and level of integration. Not iPad specific, but a great place to start when integrating technology.
Though an older post, this is still a good starting point for integrating QR codes into the classroom. The Mobile Native is a great blog for integrating mobile devices and focuses on younger students.
PE teachers are often left out when it comes to technology integration. This is a great article full of suggested apps and links for integrating an iPad into a PE curriculum.
This free eBook is available for download and provides a great interactive resources. Each section ties into some aspect of Bloom's Taxonomy and provides additional information to support iPad integration into the curriculum.
This is a great review of a standard app - iBooks. It also includes a link to a great podcast about alternate ways to integrate iBooks into the classroom
This product from the School Improvement Network facilitates administrative classroom walkthroughs in that it leverages the camera capabilities of the iPad/iPhone/iPod Touch and integrates it with assessment tools designed to give teachers constructive feedback.