It seems to crop a lot so here is a link to the first part of a lesson in learning the fretboard. It is a simple idea and uses what we already know..... the alphabet. A little basic theory is shown, a few notes named, then it shows a system that moves about the fretboard in a logical known fashion familiar to us all.....the alphabet. Since it shows only diatonic notes it is easy to relate to, I find keeping sharps and flats out of the equation to start with makes it clearer to teach. Adding en-harmonic positions later using chromatics works better as the note that is to be named sharp or flat is already known. I hope it helps a few out in learning the fretboard rather than trying to remember it.