Color Blender is a Cocoa application that was created because I got tired of finding hex/rgb values for colors and finding colors in Apple's default color picker that corresponded with hex/rgb values. It is also very helpful when coming up with a color scheme for a web-site or design to blend two colors together to try to find a matching color for your color scheme. As seen in the screen shot below you can blend two colors together and find the hex & rgb values for all the three colors.
In addition, you can edit the rgb & hex values for the colors. Through the preferences pane you can customize a prefix to be added to the hex values. You can easily copy hex/rgb values through the dock menu (as seen on the right), allowing quick access while using other applications such as Photoshop or Flash.
This was made year ago, before programs like Color Schemer Pro existed