I highly recommend SnagIt (Techsmith) for everyday screenshot and video recording.
Techsmith also makes Camtasia which takes video recording to a whole new level.
With Camtasia, you can create training CD's / DVD's with menus, insert slides, zoom in / out, add sound effects and call outs.
I work for a pharmaceutical company and use Camtasia to record the execution of software test scripts. Video is much more reliable than taking screenshots. You can't forget to take a screenshot when recording video and you can analyze just how that error message popped up. - no need to recreate the error. In fact, you can take screenshots from your video later on if you are so inclined.
I also use it to create training videos for our intranet.
I suggested SnagIt and YouTube because it is a cheap and quick way to get started. - Great for ad hoc. and great as a "parting gift" after a classroom training.
I recommend that you try out the Microsoft training videos too. Just google (or bing) Microsoft tutorial or training.
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