I want to upload a number of videos as HD to YouTube, how do I go about doing this?
Just upload them as usual, as long as the source material is in HD this is how it will be added to YouTube;
YouTube offers the option to view content in high definition with 1080p resolution — when the source upload supports it.
How do you Upload Video in HD to Youtube?
For the highest quality, YouTube now recommends the following setting for your video: MPEG4 (DivX, Xvid, H.264) format
1280×720 resolution or 1080p
128k Mono or 320k Stereo MP3/AAC audio
24,25 or 30 frames per second
Up to 2GB file size and 15:59 min. duration
YouTube accepts a wide range of video file formats such as .WMV, .AVI and .MOV but you may get the best results from converting your file to MPEG4 video with MP3 audio.
Hope this helps.