As you all know, the NAMM show (National Association of Music Merchants) was held a couple of weeks back. This is one of the largest music product trade shows in the world.
One of the many interesting products this year was something called Fret Daddy.
This is basically just stickers that you put on your fretboard of your guitar. Whats interesting about this is that you can see every notes location on the fretboard. This will not only help beginner guitarists that are unfamiliar with the fretboard and the notes location, but intermediate players as well. Its not very cheap for a few pair of stickers (aprox. 10$), but its worth it! It is available for classical guitar, bass and electric guitar.
This will definitely be used by guitar teachers all over the place.