I'm just researching this right now, but I'm looking at how one could have a user record some audio in their browser (this would obviously be either silverlight or flash) and then have that saved back to a document (from the backend). 

I think the easiest way to do this is to create just a data type that would display the flash/silverlight component and another (text string or even amazon s3 data type) to hold the url of the recording.  The flash/silverlight compontent could post to some webservices the mp3 file.. ..

Just curious of how you'd go about this?