By the way, this is in .NET. I didn't like the usual "color dialog" tool of .NET, so I searched for a better one, and I found two: (both tools are available in C# and VB)
Color Picker #1
I developed an application and I integrated this into it, by adding it as a reference. The EULA of this color picker application allows developers to do it. Feel free to post questions and comments here. :D

Color Picker #2
I haven't tried out this one yet, the GUI looks neat though! :D Can someone try this out please? And please give us some feedback here.