look at gamefaqs.com :S they nearly got everything lol :S as i remember there is one at
besaid. thunder plains.
ormus room at guadosalam.
gagazet mountains where you kill seymore.
oasis at bikanel desert.
there is one at kilika where you gotta jump up in a tree.
there is one more at kilika in donas house.
then TWO at calm lands/gagazet mountains. a little outside where you kill dark yojimpa in ffx and also in ffx-2
and then there is one more i think that i cant remember where is.
when you have found all these ones. go to bikanel and talk to marnela and then you gotta go into the dungeon to find the last one. then prepare for battle :S
in the first 8 ones that i said to you there i dont know which one is before the others