I have a recording from a camcorder (with a broken mic) where the audio is 1) largely white noise and 2) almost in-audible sound from people chatting in a room.
What methods could be used to amplify the "almost in-audible" parts (and remove the white noise)?
I guess what consumer level audio tools could do this?
From your description of the audio, it is going to be hard to fix, as white noise tends to cover a very broad frequency spectrum and so is hard to get rid of without losing what you want to keep. A decent starting point for you would be to use a freeware audio editing program like Audacity. Here is a noise removal tutorial using Audacity.
You can also use audacity to cut out sections where there is no background talking. Then you can use an effect called a compressor to attempt to raise the level of the speaking to a better level, although you may still find you are amplifying some background noise. Here's a description of the audacity compressor.
