http://www.21QuestionsAboutYouTube.comYouTube takes any format you send them, so don't worry about it. Do they take X? Yes. Do they take Y? Yes. Do they take Mac? Linux? Windows? Yes, yes, and yes.
YouTube will take any video format produced by any major, realistic video editing system. So don't worry about trans-coding or formatting for YouTube, just give them what you've got and let them take it from there. They will do everything they can to make it look as good as is possible.
Now realize, if you send them a dead duck, it's still a dead duck—it might be one of the best looking dead ducks they've ever had. Send them high quality, send them whatever format you want, and YouTube will make it look as good as possible.
More questions about YouTube answered at http://www.21QuestionsAboutYouTube.com http://www.youtube.com/watch?v=xR2TOwMmm2M