These are free and simple color manipulation tools which require NO installation and can be easily used off the web.
Color Blender — Very convenient tool to blend any two colors with a varying number of midpoints
A list of colors by name and color code — for those of us who are color blind, this is very helpful for looking up colors by name.
Color Code Chooser — tool helps you manipulate colors in a number of very helpful ways.
Check them and let me know your comments and feedback.