Incognito:

I don't think this person has any right to protection of anything she might have said in "confidence". I'm also not too concerned about the degree of harm she might cause in her new job. A cheat is a cheat. The fact that she seems to be in a position to do harm only makes it more important to turn her in.

You should go into this with your eyes open, though. How will your employers react if they find out that you knew she had faked her resume and didn't tell anyone?