[john lenihan]"I am using Sony Vegas Pro 10 on a pc. I have a client who wants my footage in full HD resolution for editing on FCP. He wants it in a .mov format."
Download the free Avid DNxHD QuickTime codec and render to that. The FCP editor will have to do the same. Avid DNxHD was designed specifically as a digital intermediary for this purpose and doesn't have any of the gamma problems that other QuickTime codecs have when transferring between Mac and PC.