I've thought of a USB cable, but since I'm having multiple camera's I would also need multiple computers. That makes everything rather expensive.
The Eye-Fi cards I wasn't sure whether they would work together with CHDK. It would be nice if CHDK could use the WiFi interface of the various P&S camera's Canon has... Also, the Eye-Fi has a known bug with the 240HS where the camera shuts off the Eye-Fi during exposure, breaking the WiFi connection.