If this guy is the dirt bag you say he is and she is as worthy an individual as you make her sound than she will find out on her own that he is a jerk.

Qusetion? Why didn??t you make your feelings known to her when you were making out with her?

If you decide to talk to her about it I suggest that you state your opinion very short and sweet and don??t sit down and have a heart to heart with her. The last thing you want to become in her eyes is a ??guy friend? that she bounces her boy troubles off of. If the subject comes up just say something like ??I hope you know what you??re doing.? Wish her the best and drop her like a hot rock. Still be cool and friendly with her but stop waiting in the wings for her. Move on about your business. If she is a smart girl she will come to all the right conclusions on her own and be back knocking on your door. When and if she does knock on that door only let her do it once. If she wonders off again don??t let her come back.