this is the way i am doing things, a little messy but it will work. I have a 1 TB external hard drive all my video files are on that is formated for PC, luckily there is only about 300 gb of video on it so far. I have been transferring all that I can to my mom's 160 gb external and the rest will be put on my desktop. The next step is to reformat the big external for mac, leave it plugged in then plug the other external in and copy files through the mac to my other external. then delete all my files off moms external and do it all over again until I have all my files on the big external formatted for Mac.