Knovio is a site that essentially turns your PowerPoint presentation into a video presentation on the web. Simply upload your PowerPoint, start recording your webcam (or use your microphone if you only want audio), advance through the slides while you’re narrating, and press stop when you’re finished. You can then review your recording before saving and sharing your presentation. The finished product includes both your recorded video and your PowerPoint slides. You can toggle the size of the video and the slides by clicking and dragging the zoom bar. Here is an example: http://knov.io/pDURz5.
Knovio is still in Private Beta mode so you’ll have to sign up and then wait for an activation code that they will send you via e-mail.
Check it out here: http://www.knovio.com/