The Appearances Window
Hit 'Shift' and 'F12' at the same time to open the 'Appearances' window.
Step3
Choices, Choices...
Look at the bottom of the window. You will see a drop-down box that probably says 'No color scheme'. Drop it down and select a color.
Step4
'OK' button-hit it!
Preview your new skin color scheme, and when you find one you like, hit 'OK'. Yay! You're done!
Tips & Warnings
Make sure you hit 'OK' or your new color scheme will not be saved!