I want to restrict control Panel access to the local users on XP Professional. But administrator must be able to access the control Panel. How can I do this?

Go in controlpannel and go to users and use parental control on the account you want to block and use application restrictions and select files that can contorl the PC like control pannel there will discription for each program on the list what it does hope this helps

Make sure you set it to the other accounts not the admin account

You need to use the Policy Editor to fine tune what an user can and can't do. This article:
How To Use the Group Policy Editor to Manage Local Computer Policy in Windows XP
Should help with that. The Users icon in Control Panel only allows you to set a user as Admin or Limited.