Wireless cameras, especially aggressively marketed X10 wireless cameras, are a danger to your privacy. Because X10 cameras broadcast an unencrypted analog signal, all anyone needs to intercept it is an X10 video receiver plugged into a laptop. That's right; someone sitting in a car parked on the street could be watching the video from your XI0 nanny-cam.
The worst part about this is that X10 remains silent about the problem and makes no effort to warn consumers. With hundreds of thousands of these cameras sold in the U.S., many people's privacy is in jeopardy and most don't even know it.
If you use an X10 camera, there really isn't anything I can tell you that will protect your privacy. You can't do anything to encrypt the signal because it's analog. The best advice is either to stop using it or at the very least don't point it anywhere you want to ensure your privacy.