I purchased a Foscam fi8910w for use in the nursery. All in all, I have been fairly happy with it. I added the in-laws to a “Visitor” group so they could keep an eye on the new little bugger and thought, hey wait a minute! There is no way to disable the audio!
After a bunch of Googling for a way to do it, I still had no answer. Turns out, at least as of this post, there is no way to do it in software permanently. This is pretty disappointing. I think many people would use a feature where external viewers could have the webcam audio disabled.
There is one way to disable the audio, though it is a physical patch, and doing so would disable it for all users – which really isn’t a good option either. If you want to disable it completely, you can stick a 1/8 inch mono plug from RadioShack or Ebay into the audio in on the back side of the camera. Doing so will trick the unit into shutting off the on-board microphone. There is a quick video of it over here: www.youtube.com/watch?v=FfMW0ED0hQg