Uxie, Mesprit & Azelf

I bet some of you don't know where's Heart Cave even if you checked webs on how to get them.. Kehehe, at least I scratch my head badly that time.. Either way, fly to Virbank City (2nd gym).. You will need Surf and Waterfall to get to Heart Cave.. Go to Route 20 from here (which is on the west).. At Route 20, head downward till you see a lake here.. Swim all the way to the left.. You will eventually see a Waterfall.. After you Water-up-ed.. Swim to the south.. And on your left.. You will see a cave in the middle of the lake..

Enter the cave and you will meet Pro.Jupiter.. Then the trio will start showing up one by one and runs out of the cave one by one as well.. After this event occur, you will be able to find those 3 in 3 different places.. They will be at lvl 65..

Uxie will be at Nacrene City (ex-2nd gym's city).. Try to enter the Museum (which is the ex-2nd gym, the place you will receive Cover/Plume fossils and the place to revive fossils).. Uxie will then comes and stop in front of the Museum..

Mesprit will be at Celestial Tower which is located at Mistralton City (6th gym)'s north.. At the top, there will be a bell.. Try walking to the bell, Mesprit will then appear here..

Azelf will be at Route 23. Fly to the PokeCenter before Victory Road.. You will need Cut, Surf and Strength here.. Go through the nicely-decorated gates at the lower side till you reach Route 23.. Once you reached Route 23, move to the left side.. You will see a Cut-able tree.. You MIGHT miss this area when you are heading to Victory Road, if so you will have to solve boulder puzzle first before getting to Azelf.. Then step on that panel like shown in the picture..Azelf will then appear.. :)