gresistor is a Gnome resistor color code calculator.

To allow for identification, resistors are usually marked
with colored bands. Often refered to as color codes, these
markngs are indicative of their resistance, tolerance and
temperature coefficient.
gResistor helps you translate resistor color codes into a
readable value. All you have to do is watch the colors on
the resistor and then enter them in the program. As you
enter colours you'll see that the resistor value changing
accordingly.