Maxpreps.com is a widely respected resource for National High School Boys Basketball rankings. The website provides free, regularly updated information on the top 25 teams using two different rankings systems: The Xcellent25 and the Freeman Rankings. By registering on the website, you can access expanded rankings and search tools.
USA Today also provides National High School Basketball rankings for both boys and girls teams at usatodayhhs.com. Each rankings page offers detailed information and updates on the top 25 teams, as well as a subsequent, condensed list of teams ranked 26-50.
Both Maxpreps.com and USA Today also provide national rankings for high school baseball and football.