Try out Doceri, which allows you to use your iPad as a control to annotate on your computer and IWB. The Doceri app is free, the Doceri desktop has a free tr...
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Great tutorial on using Doceri to control your computer. It is also great to use the voice record and then make computer tutorials. You can merge the videos by dragging and dropping them onto each other. Another great feature is the playback of the annotations in an animated way and then speeding up the playback and adding your voice at the speed you talk and not the speed you write.