I agree with moms who said to take things away, but what you take away - whether it's something long-term like a month of grounding or something shorter term, like the ability to spend one night with a pal - depends on your kid's maturity level.
Some teens still need "immediate consequences," rather than a long grounding. Having been through it with my first family, I learned that when you ground some kids for a long time, it seems like forever to them and they think, "well, I've already lost everything. What does it matter what else I do now?" and they turn around and do thing after thing after thing. Pretty soon, you've got them grounded (and ignoring it) for the rest of the year. You've lost your leverage.
Much better to take something immediately important away. Like, "Sorry, you can't go to the Mall with Jessica today because...." Or take a smaller thing away - grounding is basically EVERYTHING - like "come straight home after school" so that you have other things to take away if necessary.
Another thing I learned - if you haven't yet educated your child that your feelings and needs are just as important as hers' this is a good time to do that. Instead of just telling your daughter that her behavior is prohibited, begin telling her what you are afraid of. Begin talking to her as a human being with feelings and fears. This worked for me big-time. My kids started thinking of me as someone who had fear and pain when they disappeared with their friends for hours, failed to answer their cell calls, etc.
Good luck. This is the scariest and hardest time. My 22 and 24 year olds are human beings again, fortunately, but I have three more coming up behind, and I'm really not excited about it!