Vitamin D has reached a milestone by becoming the first company to create a working product out of HTM technology that can now be purchased (it was released in beta form in November). See here for pricing information: http://vitamindinc.com/store/pricing.php
It looks like a single webcam is still free, while for $49 you get support for two webcams in either 320 by 240 or full VGA resolution. For $199, you get support for an unlimited number of cameras at full VGA resolution (although the company does not recommend using more than 3-4 cameras for a dual core PC or 6-8 cameras per quad-core PC).
For now, the software recognizes the presence of humans in videos (as opposed to other moving objects like cars, animals, or tree brances). The future of this software will be quite interesting, as Vitamin D has already noted that it plans to upgrade the software in the future to detect more sophisticated actions in video.