If you don't mind relying on a third party I'd recommend looking into these:
USTREAM
Justin.tv
Lifestream.com
Stickam
These services allow you to stream your webcam to the world and embed it on your own site. There are also non-commecrial utillities and programs which allow you to do it without relying on a third party, but that means you will also need to provide the bandwidth for it. Depending on your hosting and/or ISP and the amount of visitors that may be expensive, or even impossible. When using a third party like the ones above you will only need to stream to them, they take care of the rest no matter how many people are watching. In exchange they might include a advertisement or try to attract your visitors to their site.
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