This are useful tools to get the colours of your map to work together. I would be really interested to hear how our resident industry pros (and talented amateurs) go about colour selection:
http://wellstyled.com/tools/colorscheme2/index-en.html
http://www.limov.com/colour/schemes.lml
http://www.colorschemer.com/online.html
http://www.degraeve.com/color-palette/
http://www.colorbrewer.org
http://mudcu.be/sphere/
http://kuler.adobe.com/
http://colorschemedesigner.com/
http://www.tigercolor.com/
::Edit:: added the links below to the OP
