Wideo. Wideo allows you to create short, animated videos and Common Craft like videos in your web browser. Today, Wideo announced that you can now upload your own audio files into your video projects. This means that you could record a voiceover and add it to your video.
WIDEOO REEL ENG NEW LOGO from Agustin Esperon on Vimeo.
Applications for Education
With Wideo's new voiceover tool you could really have your students creating explanatory videos in the Common Craft style. The art of Common Craft videos is the way in which confusing topics are boiled down to a concise explanation. If your students can do the same with a topic in your class, they can prove that they know the material.
My recommendation for a simple voice recording tool is SoundCloud.