Once you’ve finished editing your video, made sure it's less than 10 minutes, smaller than 100MB, and in an acceptable format, you're ready to upload it.
Click "Upload Videos" in the upper-right-hand corner of any YouTube page.
Enter as much information about your video as possible, including Title, Description, Tags, and Category. The more information you include, the easier it is for users to find your video!
Determine if you want your video set to Public or Private.
Click the "Upload a Video" button.
In the next window, click the "Browse" button to browse for the video file. Select the file you want to upload.
Click the "Upload Video" button.
It can take from a couple minutes to an hour for your video to upload to YouTube.
If you're receiving an error with your Upload, you might want to make sure you're attempting to upload a file that's recognized by YouTube. YouTube accepts video files from most digital cameras and camcorders, and cell phones in the .AVI, .MOV, .WMV, and .MPG file formats.
There is more help here:
http://www.google.com/support/youtube/bin/topic.py?topic=10524
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