For the times that you feel the need to have a camera in the room for security purposes, the iVigilo Smartcam Pro is the perfect app to have.
The iVigilo Smartcam Pro is an app that will transform a mobile device, iPad or iPod into a security camera. This has a motion detection system that will activate the cam if it senses any movement. This will result in the alert picture being sent via e-mail or Twitter. The Smartcam Pro also has live broadcasting ability to the Internet so that users can keep watch at all times.
This is a pretty hand app, but remember that users should keep their iOS device hidden well so that it doesn't get stolen.