Okay, here are the locations of all 5 moon stones. 3 are visible, 2 aren't.

1.In the upper left hand corner of the first floor of Mt. Moon.

2.In the basement of the game corner.

3.In the bottom-right corner of Route 2 (Use CUT).

4.In Mt. Moon, before the supernerd's platform, there is a corridor 4 spaces long and 1 space wide. Go to the end of it and press A.

5.In the Pokémon Mansion on Cinnabar Island, go up to the right side to the 5th pillar. On the right-hand side near the entrance. Press A.