I think it was Free Technology for Teachers where I first heard of Brainshark. Think Slideshare and add video, url, document and photo slides as well as the option for recording or uploading audio files. It uses Flash, so I was not able to try creating content on the iPad. There is an iPad app for viewing content on the site however.
I made a very short (and very poor) example just to try it out. After many dramas with Flash crashing on my netbook and the built in microphone not picking up any sound, I finally restarted it, plugged in a headset mic and used Firefox without too many dramas. It has not been without some challenges, but that may very well be my particular set up, rather than a Brainshark problem.
Brainshark offers a selection of audio files that can be used for background audio and the volume level can be adjusted so that voiceover recording can be heard.
I think I’ll be trying this again. And here is the test presentation I created.