I understand from some threads here that digicams acting as mass storage devices do not need special drivers to download through usb - Nikon and Olympus for example - as they use the usb-storage module and can simply be mounted and inspected with a file manager. Does anyone know if the Pentax Optio 33WR is one of these, and if there is a way of finding out for any camera whether it is or not?

Most such devices that can be connected by USB can be read by linux. The Flash memory id formatted as a FAT partition. Actually you could run Linux from your camera!

Thanks for that - sounds encouraging. I have just been playing with a very cheap little digicam with a usb connection and it is found but does not seem to connect to the usb-storage driver. Here is last few lines of dmesg:

Initializing USB Mass Storage driver...
usb.c: registered new driver usb-storage
USB Mass Storage support registered.
hub.c: new USB device 00:07.2-1, assigned address 4
usb.c: USB device 4 (vend/prod 0xc25/0x310) is not claimed by any active driver.

What can I deduce from this? This camera does not work with it or have I missed something?

Found the answer to my first question here:
http://www.teaser.fr/~hfiguiere/linux/digicam.html
and it is YES! No sign of the cheapy one though.