Although recently discontinued, the Flip series of HD handheld cameras can get you into the world of HD video - but unless you also purchase an audio adapter for the later models, you have no MIC IN to improve the audio.
Logitech offers several well-reviewed Web cams - and the top of the line has very good audio.
Purchase - and use - a tripod. You do not want to cause folks to vomit on their keyboards from motion sickness with unnecessary handheld shots.
I found a great deal of good information at this site ...
http://www.handheldhollywood.com/Clint K6LCS