iRiver iFP driver

Just a note to say that all of the 'GROUP="ifp"' lines should be at the
end of the preceeding line, not on their own. Damnable line wrapping!

Alternatively create a file in /etc/udev/rules.d called ifp.rules with the
following contents. As with your solution, you must be a member of the ifp
group.

--- begin file ---
# udev rules file for supported USB devices
#
# To add a USB device, add a rule to the list below between the
SUBSYSTEM...
# and LABEL... lines.
#
# To run a script when your device is plugged in, add
RUN="/path/to/script"
# to the appropriate rule.
#

ACTION!="add", GOTO="libsane_rules_end"
SUBSYSTEM!="usb_device", GOTO="libsane_rules_end"

SYSFS{idVendor}=="4102", SYSFS{idProduct}=="1001", MODE="660",
GROUP="ifp"
SYSFS{idVendor}=="4102", SYSFS{idProduct}=="1003", MODE="660",
GROUP="ifp"
SYSFS{idVendor}=="4102", SYSFS{idProduct}=="1005", MODE="660",
GROUP="ifp"
# iFP-780
SYSFS{idVendor}=="4102", SYSFS{idProduct}=="1007", MODE="660",
GROUP="ifp"
SYSFS{idVendor}=="4102", SYSFS{idProduct}=="1008", MODE="660",
GROUP="ifp"
SYSFS{idVendor}=="4102", SYSFS{idProduct}=="1009", MODE="660",
GROUP="ifp"
SYSFS{idVendor}=="4102", SYSFS{idProduct}=="1010", MODE="660",
GROUP="ifp"
SYSFS{idVendor}=="4102", SYSFS{idProduct}=="1011", MODE="660",
GROUP="ifp"

LABEL="libsane_rules_end"
--- end file ---

Naturally only the lines pertaining you your particular device matter, but
this is a general solution. Any other product ids would have to be added as
well.