Since I hate the idea that a camera can start-up when I don't want it to. I'd like to break it without breaking it 
Simply software disable the camera by moving a QuickTime component called USBVDCDigitizer.
First go into the directory which contains the component.
cd /System/Library/QuickTime |
Then create a directory that would contain the component as a backup in case you would like to restore the component again.
sudo mkdir .ComponentBackup |
Now move the component in the backup directory.
sudo mv QuickTimeUSBVDCDigitizer.component .ComponentBackup |
As last, be sure nobody can access it, use chmod to secure the permissions on the backup directory.
sudo chmod 000 .ComponentBackup |
Now if you would launch something like Skype, MSN or iChat and check the video settings you might notice that the camera would still be active. Just leave it open for a second... It will disable but it takes a bit time to get notice of the component being gone.
And there you go, no camera