Currently Being ModeratedJul 8, 2013 6:23 PM (in response to walkdontrun)
You don't mention whether or not you used a green/blue background... without that, your biggest will be keying.
If I understand you correctly (and you shot green) then all you need to do is pick a sync point like the first word of a sentence and mark each clip. That will allow you to visually check the sync as you work out the compositing details. When the comp is complete, delete the audio from all but one track.