I second everything said by SRH, especially as this is a situation you can't really win.
If she isn't aware of the situation she is causing or doesn't like it (I have a gorgeous, popular friend who hates the attention she gets from male bosses because it pits her against the rest of the office) then you are being unfair to her.
If she is deliberately causing these problems then what can you do about it? I used to work with a girl who always wore a skirt that barely covered her knickers and a VERY low cut top. She would spend all day flirting with the male bosses. She would get let off the horrible jobs and allowed to leave early etc. But we couldn't do anything about it as if anyone spoke out against her we'd be accused of being jealous of her.
I agree that you should be nice (or at least civil) to her. If she is an innocent she will appreciate it and if she is not at least your colleagues will see that you are a mature, professional person.