Mark, first you should be glad that the all you have to worry about is her speeding. There are so many other things a Teenager can do to get in trouble 
When I was 17 I drove like a complete idiot, to be honest I don't entirly know how I survived as I often drove up to, and past the limit, and even ended up in the odd ditch as a result.
What slowed me down though was similar to what LBaldwin outlined below:
A defensive driving course that outlined hazard awareness and pointed out that you share the road with other people, who all use it in different ways.
A track day with experianced instructors.
It was a practical experiance of emergancy stopping, swerving, hazard avoidance etc. As well as free laps of the track that gave a very good indication of just what happens when you do lose control (I made good use of the run off areas
).
Actually having an accident.
Ironically while I was traveling at the speed limit, someone else ran into my car. It was completely destroyed, and I have a permanant neck and shoulder injury as a result.
If I had been speeding it could have been much, much worse, and if I had been really paying attention, and traveled below the speed limit with the rest of the traffic, I would have avoided the accident altogether.
Rather than saying "These are the rules, follow them".
I was taught "Here are the reasons for the rules, here is what happens if you don't follow them." and "You need to drive to the conditions, the speed limit is only an upper limit".
Now everytime I drive with my Father I am the one telling him to slow down.
I suggest you show this thread to your daughter, and point out options 1 and 2 above, before she has option 3, which I do not recomend.
LBaldwin wrote in post #7188816
I had serious issues in the driving department prior to my 18 BD. Including stealing the family car (basically took it w/o permission) and a DUI that could have gotten someone seriously hurt or worse. 1 month is easy peasy.
Eventually after learning how to drive professionally (something not really available to me as a kid) I learned HOW speed can kill and exactly what skills are needed to survive to my just turned 48 BD, something many of my family didn't really expect of me.
Get her to a Bondurant style of defensive driving, where she can experience skid pad, emergency manuevers etc. They will show her the actual physics of driving, something sadly lacking in most courses. I took several classes in the ARMY at Ft. Bragg, tractor trailer, motorcycle, executive protection etc, all of them very worth while.
The alternative is to take her to the track with a pro driver and scare the sh*t out of her.
At 17 you really do think that you are invincible...
EDIT: In other words punishment is warrented, but improved skills will keep her alive - which is really the goal. Skip Barber is a real hoot, and I think you may want to go togeather...
http://www.skipbarber.com/default.aspx