It allows to adjust camera parameters like aperture, exposure or zoom remotely from your computer. It displays a live viewfinder image on supported cameras (most Powershots should work), which can be overlaid with the last captured frames (multi-level-onion-skinning). An integrated editor lets you review the captured frames and remove unwanted ones. These aren't deleted but moved to a subdirectory.
Unfortunatelay, Canon's compact cameras don't allow the focus to be manually set while in remote-control-mode. On the other hand, the live-preview is too low-resolution to decide whether the auto-focus correctly adjusted to your scene. csmc offers a workaround: if you check 'af-preview' everytime you click 'af/ae' to set the focus (that is, let the camera guess it), it takes a frame. This frame is set to be low resolution (640x480) but high quality to be transfered and displayed quickly but allow for judging the focus. The preview-frame will be instantly displayed, to return to the viewfinder, click on the image.
NEW: version 0.7 is available in english