This is what I used to mount the Mandrake Pendrive Linux loopback device to retrieve my partners files when she moved back to a proper PC with a working hard drive
# Create the device as /dev/loop0 and point to the loopback file
losetup /dev/loop0 Desktop/mcnlive.loop
# Mount the device in the usual way
mount -t ext2 /dev/loop0 Desktop/vfs