The question really is: Does iTunes play _all_ files that play in QT player? And the answer is: No. Somehow, I think, Apple has restricted iTunes so it plays only "clean" QT-codecs, i.e. .mov files, .mp4 files etc., but not any .avi's that QT can play etc. So you'd really have to reencode them, which'll take _quite_ some time and lose quality. Too bad...