Here you can download the VariohmMeter Windows Sidebar Gadget.
It allows you to translate the color code of a resistor to its value. Here is a demo of the tool, in case you want to try it first.
Download the gadget (8KB).
The gadget has been digitally signed.
When the gadget is started and when you change the settings, you must have a working internet connection.
In the settings screen, you can change the language (Dutch or English) and you can switch bewteen carbon film (3 rings) and metal film (4 rings) resistors.