Looks like it would be fairly easy for an amature tomistake a Pileated woodpecker for an Ivory bill. I took this photo of a Pileated in the yard just a few weeks back.
http://www.worldisround.com/articles/54892/photo276.html
That is really cool!
I have a pair of downy woodpeckers in my yard but I have not seen them since the winter.
Here's a link to a discussion about the video clip and it includes a link to the video.
http://news.nationalgeographic.com/news/2005/04/0428_050428_extinctwoodpecker.html
For two year, I lived in a second story apartment that faced a cornfield, and a huge tree was right next to the balcony.
I set myself up an entire feeding station on the balcony.
The first winter, I had a female pileated coming to the suet. Like clockwork, every morning I could hear her 'cuk-cuk' as she flew towards the tree. So I could stop getting ready and go watch her feed, for as long as 4 minutes sometimes. By the end of spring, her mate and at least on offspring were coming. Once I walked out onto the balcony just as a male was flying off the roof onto the suet. He caught a glimpse of me and jumped to the other balcony. I froze and we just stared at each other. He was not 10 feet from me.
I think most reports of ivory-bills over the years are pileated - however it should be pretty obvious from a video of a flying bird. The big obvious differences don't show up in the head-shot...
http://www.audubon.org/bird/ivory/differences.php