KishKish Lie Detector is a software which will analyze the stress in the voice of the person who is talking to you.
From the Website
KishKish Lie Detector offers you a tool to detect the stress level of the person you talking with over Skype™. With the use of KishKish Lie Detector you can monitor in real-time the stress level of the person you talked with. This allows you to gage the level of stress and modify your questions in real time.
Download it here