You catch Cresselia
at full moon island use your action replay and go directly right into the water. you will get it at another island.
It releases the Pokemon you have just caught =( sry
There isn't actually a specific place were you catch cresslia. you first meet it at full moon island. then you go to your poketch,and if you have it, there is a program which will let you see were cresslia is wandering around in pearl. really after you first meet it at fullmoon island, the net time you see it will be somewere random.
head east from full moon island to get to new moon island
you find cresselia on full moon island
You have to get the National Dex, then go to Full Moon Island.
visit full moon island and look for it in the wild
The lakes, Spring Path, Stark Mountain, Full Moon Island, New Moon Island, etc.
there is no fire island on platinum there is full moon island and crsent moon island (were you catch cresilia and darkria) and iron island that is it
you will be needing a member card on wfc but around in 2010 its free but I don't know if you can get it free after getting it go to the house behid the pokemon center in canalave then you will have a dream that you're in full moon island
you first need to go to canalave city and talk to the sail boat guy and hes says do you want to go to iron island and he says do you want to go to full moon island (and you need to beat the Pokemon league) hope this helps
catch a feebas and give it beauty poffins until its beauty is full then get it up levels hope that helps