Plural Eyes is one of the easiest ways to sysnc sound I have ever seen. This FCP plug in has been around for quite some time, however it is worth mentioning if you have not tried it yet. Shooting sound with HDSLR’s is a pain. Separate sound is the best way to capture good audio. Plural Eyes makes shooting with separate sound so simple even I can do it. The software works off of the sound waveforms to sync with the “scratch track” recorded onto the camera. In FCP you simply name the clip “Plural Eyes” and with one click, it will automatically sync the sound for you. It is that simple.
***UPDATE The Retail Price for Plural Eyes is $149.00, The $119 Price applies to the Windows Version Until September 17th, 2010. Thanks for pointing that out.