Internet Explorer Parental Controls
This feature is included in the following editions of Windows Vista:
Internet Explorer 7 in Windows Vista gives parents the ability to create filters and settings to block children's access to objectionable content and approve access to trusted or acceptable sites.
Parental Controls can also block all file downloads, offering another way to keep malware (including viruses, spyware, and other threats) from infiltrating your PC. Internet Explorer 7 works directly with Windows Vista Parental Controls to provide a single interface to help you manage all settings and reports.