Tellagami is a new app I saw this summer (and then was reminded about it today when I saw the post from Free Technology for Teachers). This is a free app that allows you to create a short (30 second) video with a customized avatar and a background image. You can change the appearance of the avatar, use one of their background photos or upload your own, and then either speak or text your comments. Please take a look at the Free Technology post- there are several suggestions for using it in the classroom. With the new Discovery Education board builder, you could pull a gami into a board- that would make student use really simple.
They can be emailed (that will be an issue for our school iPads), but they can be saved to the camera roll. I emailed this sample and then got the embed code yet that was a very small image. The one below was from a YouTube upload.