Pedal Wench is correct on that! I wear a medium short but a small jersey! It fits like a glove which is how I like it. No wind drag, aero as one can get if not in a skinsuit.
I am also 5'6 and probably 135.. not sure haven't been on a scale in ages.. I normally wear a medium shirt in regular clothes and a 4/6 bottom. And umm I am a 34B if that helps with those measurement areas.

This is for the '07 jersey.