The hardest part of editing my video for use on Flickr was getting Flickr to recognize it with a 16:9 aspect ratio. I was reducing the resolution to make a smaller file, and every time I did, Flickr would squish it into a 4:3 aspect ration.
Finally I found that using a resolution of 640x360 would result in a nice widescreen video on Flickr.
This was captured from a Canon HV20 HD camcorder with a wireless mic and loaded into Linux using dvgrab. Editing was done in Cinelerra and the final resize and conversion for upload to Flickr was done with ffmpeg.