Looking to show video through webcam

I'm looking to show videos through my webcam, like a virtual camera. Like in video conferencing programs such as yahoo and AIM and msn, I would like to broadcast my webcam feed with video clips. Does anyone know of any mac programs that can do this? I found two programs for Windows that can do this:
Video2Webcam - Show video clips during video chat even without a real webcam
and
Home - Simulate WebCam by Software

That is what I am looking for, to show video clips during video chat without a real webcam. Can anyone help me out? Thanks!