I don't know about adding a live feed to your site, as unless you are hosting the site off your own computer, it would be fairly difficult, not to mention the bandwith requirements etc... If you are looking for a quick and cheap solution that uploads a pic from your webcam at your computer and automatically ftp's it to your website on a scheduled period of time, you can check out this:
http://www.theill.com/conquercam/
I just did a quick search, but others may be able to provide better advice, as I have never tried this myself.