Web cams and IP cameras have come down in price while quality has improved.  The problem is that the webcam/IP camera has never really had a great security program to make them useful outside of video chat.  That may have just changed with Vitamin D’s security software.

Vitamin D Video detects people and moving objects in video streams for security and monitoring purposes. It runs on a PC or Mac, and uses off-the-shelf USB webcams or network (IP) cameras.
For the first time, professional performance with real-time alerts is available to everyone.

Not sure how much the product will cost but it is free while in Beta until January 31st, 2010.  Video of Vitamin D security software in action after the break.