Even i am looking for the tool that can download the videos also from the web
page.
There arer some web pages that can download the video from you tube but not
the entire web page: <http://keepvid.com/>

The web page that i am looking for  download are:
<http://nptel.iitm.ac.in/>
<http://www.khanacademy.org>

If any of you can come put with a soulution please update me ...