Excellent article about 6th grade math students using iPads, along with Explain Everything and Book Creator apps, to produce "iBooks on solving One-Step Equations."
From Explain Everything:
"Explain Everything is an easy-to-use design tool that lets you annotate, animate, and narrate explanations and presentations. You can create dynamic interactive lessons, activities, assessments, and tutorials using Explain Everything's flexible and integrated design. Use Explain Everything as an interactive whiteboard using the iPad2 video display. Explain Everything records on-screen drawing, annotation, object movement and captures audio via the iPad microphone. Import Photos, PDF, PPT, and Keynote from Dropbox, Evernote, Email, iPad photo roll and iPad2 camera. Export MP4 movie files, PNG image files, and share the .XPL project file with others for collaboration. Explain Everything has been designed for use in educational, business, and entertainment settings."
From ShowMe:
"ShowMe is the easiest way to create and share lessons on iPad. Create beautiful video tutorials with the tap of your finger and share with your students."
From Red Jumper (app developer):
"The simple way to create beautiful books on your iPad. Read them in iBooks, send them to your friends, or submit them to Apple's iBookstore."
From Educreations:
"Educreations is a recordable interactive whiteboard that captures your voice and handwriting to produce amazing video lessons that you can share online. Students and colleagues can replay your lessons in any web browser, or from within our app on their iPads. Check out the "Showcase" on our homepage or the "Featured" tab in our iPad app to view some great lessons that other teachers have created with Educreations."