WOW!  This is slick.  Logitech has published a sidebar gadget that works as a motion detector.   When you click the play button it starts watching for motion.  Any movement gets recorded as a video and placed in your videos folder.  It works!  Try it out!  The only caveat I've found is to leave the resolution as default.  I cranked it up to 800x600 and it crashed when I activated it.  Resetting it to 320x240 fixed the glitch.

http://www.logitech.com/index.cfm?CONTENTID=13265&CRID=2203&PAGE=products/topics&countryid=19&languageid=1

Now I can finally prove to my wife it's HER dog that chews up the garbage, not mine...  ;-)