Yep, there really is a HS National Champ (or there was a national tournament which included HS teams from around the country).
Go here for tourney details/brackets:
http://www.and1.com/HSNC/index.asp
Go here for article on the championship weekend in Philly:
http://www.philly.com/mld/philly/spo...ll/3665369.htm