When I was in High School (1976-1979),
we had a teacher that taught an elective class
on "computer" and BASIC programming. We used
DEC-Writers and Teletypes connected to a TIES Server.
That class is what got me hooked on programming and was
the basis for all of my training thereafter.
I feel teaching PHP especially would be the greatest
thing, and could even affect the future of student(s).
If you can't get permission to teach during the day,
you should volunteer to stay after and teach it as an
after-school "club" on your time. It sounds like you
might have a passion for teaching, and this could