It has an internal buffer, but it is used for short-term storage only.
There is a Canon utility called EOS Capture which allows you to "tether" the camera to a PC to import photos straight to the PC from the camera. This should be a part of the software package that came with the camera. (Should be part of the "Digital Photo Professional" or "ZoomBrowser" software.) I am unsure whether it requires a CF card to be in the slot. It seems like this should work, but I can't seem to Google anything that explicitly says so.