iPod Interactive Content
Check out iWriter software ($30 Mac or Windows). You can try it free for 15 days. iWriter lets you create projects with text and audio. The project can be eBooks, lecture notes, quizzes, and more. They are like little webpages for your iPod. When finished creating, iWriter saves projects as installers for Macintosh and Windows computers. The installer can be placed on a CD, flash drive, web site, blog, or server to be downloaded and installed onto iPods by others. Try downloading sample Interactive Stories School Day and Crazy Hairdo. Follow the installer's instructions and then view on your iPod. It's a short "Choose Your Own Adventure" eBook. Learn more about these stories here. Make your own stories by downloading my Interactive Story template for iWriter here (iWriter must be installed).
View a video tutorial of making projects with iWriter to learn more.
If you're interested in content that is already made, check out U Fill It Up. They have audio, video, glossaries, and quizzes for many different topics. Topics include What is Physics, The Oceans, The Great Depression, and What is Physics. Most topcis cost $4.99 to download, but your first one is free.
Another place for pre-made content is iPREPpress. They have dictionaries, study guides, and historical documents that you can purchase and install in the Notes section of a iPod.