There is a workaround...although not a great one. It would require you to leave the video feed visible on your desktop whenever you want to monitor the video via iCam. If that isn't an issue, you will need to download/install ManyCam (free)....then under sources in ManyCam, choose Desktop > Custom Desktop. You will want to make sure and locate the video feed on your desktop in an area that would not be interrupted by popups, error messages, etc (to keep from triggering a false motion event). I have no idea how good/bad the quality of the video would be (I would force your image size to 640x480 in ManyCam...and possibly choose the "Improved Quality" option). Once you get it all set up, you will choose ManyCam as your source in icamsource.
I'm not sure if the screensaver would interfere with this working correctly...but if you try it, please let me know. I am curious...just not curious enough to set it up myself.