No problem.  If you are running the latest version of the Operating System (called Vista) you can easily set up parental controls to view web pages visited (even if she clears her history), set time limits, block websites (or groups of sites based on category), and even record IM conversation.
First set up two accounts on the computer, an admin account and a managed account.  To do that you need to go to the Account button on the control panel. Make sure you are the administrator and your daughter is the managed account.  Now you can click on the parental control button and set the controls you want to use.
You can watch the Parental Control video in the Video Library for more information.  Just remember that your daughter has access to other computers at school or a friend’s house, so setting these parental controls without a conversation about why is only half the story.  You are doing this to set up expectations and NOT to keep her safe.  Your eyes and ears are always the best parental controls you have!