We use VoiceThread in a lot of our EdTechTeacher workshops as it is completely web based and now includes an iPad app. As a tool, it can create digital stories, be used for foreign language exercises, or support the creation of collaborative study aids. This library is a database of articles about successful VoiceThread projects.
This is one app that almost fully replicates the online version. The mobile version of VoiceThread leverages the built-in capabilities of the device to easily create new projects.