In terms of presentations, you can imagine combining live-action with infographics and a product demo. This is an involved process and requires production and editing knowledge. Fuel for thought--imagine taking Jonathan Harris' presentation of 20 minutes and editing it down to less than 10 with a focus on facial close-ups, infographics, and product demonstrations.
http://www.ted.com/index.php/talks/view/id/144
Camtasia is the de facto one for PC. I use iShowU on the Mac and produce it in iMovie. The default settings in iMovie hose it (i wrote a short tutorial here with the settings I've found to work best-> http://www.scrollinondubs.com/2007/06/12/produce-a-clear-scr...)
I've also heard that Snapz is good on the Mac but have not used it personally.
For screencasting: keep it under 5 minutes, use a script, read the FreshView Post: http://www.freshview.com/thoughts/2007/05/how_we_create_walk...
In terms of presentations, you can imagine combining live-action with infographics and a product demo. This is an involved process and requires production and editing knowledge. Fuel for thought--imagine taking Jonathan Harris' presentation of 20 minutes and editing it down to less than 10 with a focus on facial close-ups, infographics, and product demonstrations. http://www.ted.com/index.php/talks/view/id/144