I wear a women's medium, but cycling clothes are meant to be snugger. I'm not comfortable with that, so I usually wear a large or extra-large depending on the manufacturer.
I agree clothing manufacturer's are sizing clothing differently. Technically, I wear a size smaller than I did in high school but I'm not kidding myself into believing it.
Hincapie, however is race fit--I can't squeeze one arm into an XL. Bummer because I'm a fan and the designs are cool.
"Well-behaved women seldom make history." --Laurel Thatcher Ulrich
'09 Trek WSD 2.1 with a Brooks B-68 saddle
'11 Trek WSD Madone 5.2 with Brooks B-17