GrabberRaster is a new take on an old idea: making screen grabs more efficient. GrabberRaster makes it both easy and convenient to capture almost any picture or graphic that appears on your Mac screen. Correctly handles grabbing images for use in video projects.
With a paid license, screencast anything that appears on your Mac screen as a virtual camera, compatible with most QuickTime/webcam applications.
Combined with CamCamX (also from b-l-a-c-k-o-p.com), you can perform live video mixing of your built-in iSight camera and screencasts, sending the mixed feed directly to Yahoo Messenger, Skype or any other camera-enabled application.