it depends on your kernel and supporting software.
you need modules:
usbcore
uhci
ehci
usb_storage (which need to have support for your reader/flash devices)
and support for the files system the device is formated in -- (cameras and such are usually dos or vfat or some ms hash)
you should be able to see the device when these modules are loaded or builtin and the device is attached, as /dev/sda if this special device did not previously exist otherwise /dev/sdb or what have you.
you would mount it (if you didn't make a desktop link):
mount -t vfat /dev/sda* /yourdirectory
*****note: the usbfs may need to be mounted, this usually mounts a boottime
kernels 2.6.9 and 2.6.10 have a new ub device that is autodetected much better and r/w's faster and more reliably.
2.6.9 is a whack job though stick with 2.6.10.