CampFireNow has a voice chat over the browser. It seems that you do not need any plugins to install to get it working. This is a contrast to Gmail, where I needed to install an app.
I would like to implement a similar feature for my application. Is there a way to do this without requiring a plugin?
I've never used it, so I can't look at the source. I don't believe that there is a way to do this without any plugins at all, though. My guess is that they are either using Flash or Java (probably Flash).
Flash or Java would be the only things that would be browser agnostic. Else, you definitely need a plugin, unless the specific browser provides you a method to record.