there are some ways to make up a color picker. if dont want to use the windows standard dialog, you might try it the way i did it. it uses a background image from which you can choose a color. it also uses PNGlib by Thomas Bleeker (http://www.madwizard.org) <--- thx for it :)
you can get it from here, or from my site at http://ploptor.has.it
you can get it from here, or from my site at http://ploptor.has.it
updated version available. seems pretty much finished now...
again, either here or at http://ploptor.has.it
again, either here or at http://ploptor.has.it