Windows SteadyState is a free tool from Microsoft to perform exactly what you are looking for. It is also easy to setup and manage, and appears to be a great fit for your kiosk rollout.
Windows SteadyState includes the following features to help you manage your shared computers:
Windows Disk Protection – Help protect the Windows partition, which contains the Windows operating system and other programs, from being modified without administrator approval. Windows SteadyState allows you to set Windows Disk Protection to remove all changes upon restart, to remove changes at a certain date and time, or to not remove changes at all. If you choose to use Windows Disk Protection to remove changes, any changes made by shared users when they are logged on to the computer are removed when the computer is restarted.
User Restrictions and Settings – The user restrictions and settings can help to enhance and simplify the user experience. Restrict user access to programs, settings, Start menu items, and options in Windows. You can also lock shared user accounts to prevent changes from being retained from one session to the next.
User Account Manager – Create and delete user accounts. You can use Windows SteadyState to create user accounts on alternative drives that will retain user data and settings even when Windows Disk Protection is turned on. You can also import and export user settings from one computer to another—saving valuable time and resources.
Computer Restrictions – Control security settings, privacy settings, and more, such as preventing users from creating and storing folders in drive C and from opening Microsoft Office documents from Internet Explorer®.
Schedule Software Updates – Update your shared computer with the latest software and security updates when it is convenient for you and your shared users.
SteadyState supports Windows XP Professional, Home Edition, Tablet PC Edition, as well as Windows Vista Business, Enterprise, Ultimate, Home Basic, Home Premium, and Starter. The hardware requirements are the same as for Windows XP and Windows Vista, so any computer that runs these operating systems well should also be able to run Windows SteadyState.