Discovery Education has a huge amount of great resources for educators, from videos to lesson plans to e-textbooks and more. Some of it is in Flash, so you can't access it directly on your iOS device browser. However, iSwifter has partnered with Discovery Education to create Rover. Rover is an iPad browser that allows you to access Flash based content. The Flash content does not run on the device. It is streamed to the Rover app.
It allows you to browse and play Flash content, meaning you can now access Discovery Education's massive resource collection of lesson plans, apps, and materials.
Discovery Education also has an iPad friendly site.