For an in-depth look at the NFHS rules buy the Redding Guide:
Home Page
The NFHS usually has their football rules meeting in Jan/Feb so the 2009 Redding Guide should come out in May/June, somewhere in there.
You can also read through these:
Football Files
The link to Penalty Enforcement (not All But One Penalty Enforcement) is a great framework for applying most any penalty to any situation.