Britt Bravo at NetSquared is asking for your best thoughts about this question: How can nonprofits use online video to raise money online?
I don't have many good thoughts on this topic, but at the Making Media Connections conference in Chicago, Michael Hoffman did a workshop on incorporating video into nonprofits messaging. He was presenting the same time as me, so didn't attend. However, his post summarizing the resources and presentation are an excellent resource.
I'd also point to Katya Andresen's "Constructing Your Call to Action" and while it isn't video specific, these are important guidelines about your ask.