Mashable has produced an extensive guide on all of Google+'s key features, as well as an introduction to the service and the important things you need to know about it.
Moglue is a new program, available for Mac and Windows, that enables you to create interactive ebooks and publish them to Android and iOS devices. Your ebooks created with Moglue can include videos, images, and audio files that you import from your computer. Moglue supports a wide variety of file formats for image and video content. When you have completed constructing your ebook you can publish it to the Moglue bookstore where it can be downloaded onto your Android or iOS device.
Taking the Mystery out of Copyright is a site from the US Library of Congress that uses animations to teach about copyrights and copyright laws. It's fun and educational and easy to understand.
The Library of Congress also has a lot of other great resources for educators.