There are two websites that are useful for obtaining schedules:

www.highschoolsports.net    This is the one used by many of the Athletic Directors so when a late change is made, it will be reflected on this site.  This site is best if you are looking for the schedule of a particular team.

Another is www.clehssports.com   This site includes past results as well as upcoming games.  It also has a function where you can view all games that are being played that day.