A short documentary by Brighthand Pictures:
The results of her experiment aren't at all surprising: changing one's appearance to be more sexually inviting clearly has an effect on the way one is treated by others, particularly for women. We all know it - this isn't rocket science.
However, the woman in the documentary (intentionally, or more likely unintentionally) exhibited a subtle change in her interpersonal style when dressed differently that may also have influenced the way she was treated (although I'm sure the change in her physical appearance accounted for the majority of the effect).
When she dressed up more sexy, she became more outgoing/gregarious. This phenomenon - i.e., dressing sexy to feel sexy - appears to be largely universal. When people dress up, and make an effort to make themselves appear attractive (or what they believe makes them appear attractive), they generally report feeling a boost in self-esteem and confidence, and are more outgoing. This, in turn, increases their attractiveness, as perceived by others. Physical attractiveness becomes interpersonal attractiveness.