[WindowsCentral.com]

My webcam is on, but nobody's home — how do I identify the app that's using it?
If you've already experienced the unease of seeing your webcam light come on when you aren't using it, you might be one of the countless people who covers the little camera with a piece of a sticky note or sticky tack. Some malicious programs that hijack your webcam can disable the LED that lets you know when it's turned on.

Full story from the WindowsCentral blog...