I wasn't sure what color I was either, but if you catch the MA's at a non-busy moment, they'll help you out. I could never find the right color foundation, and she matched me perfectly in five minutes. Only thing to tell you is there are two categories, NW and NC. They're pretty much backwards, so if you have cool tones in your skin you're in the NW category, if you have warm tones in your skin you're an NC.
Michelle