Beach: Past the pikachu's surfboard, turn back and look for the pile of rocks, the focus sensor will turn red when they are lined up correctly, sign 1: kingler rock Tunnel: for this sign you need the pokeflute, when you see the pikachu near the egg lure it over to the egg with apples, play the pokeflute and a zapdos will appear out of the egg ([o] if you haven't got it yet) and start the generator, further on you will see a projector with some stuff in the way, take a photo of the shadow, sign 2: pinsir shadow Volcano: near the start of the course you will see a volcano with smoke out of it, throw a pester ball in the volcano and follow the smoke up until your focus sensor goes red, take a photo (it kinda looks like a koffing), sign 3: koffing smoke River: When you wake the vileplume up with the pokeflute the tree above it kinda looks like a cubone doesn't it, well take a picture and there you have it sign 4: cubone tree Cave: near the weepinbell look to your left where the 3rd koffing is, take a photo of the stars it will develop to become sign 5: mewtwo constellation
Valley: this is the most easiest sign to spot, it is right in front of you at the start of the level, sign 6: dugtrio mountain
now you can go to the Rainbow cloud.