One of my all time favorite things to do is dye my spun fiber. The easiest and most non toxic dyes to use are Kool-aid or food coloring. I also like the vivid colors commercial dyes give but prefer not to use too much of them as they require special pots and pans. Here is a picture of a variety of colorful fibers both during and after the process. Check out http://www.knitty.com/ISSUEfall02/FEATdyedwool.html for a comprehensive color chart of Kool-aid colors.