Location
X coordinate, Y coordinate

Baaj Temple (Get Anima here if you got all secret treasures from the other temples)
11-16, 57-63

Sanubia Desert
12-16, 41-45

Besaid falls
29-32, 73-76

Mi'ihen Ruins
33-36, 55-60

Battle Site
39-43, 55-60

Omega Ruins (quite tough dungeon, great for grinding)
69-75, 33-38

Also there are three passwords for three grea equipables.
GODHAND (Rikku's Celestial)
VICTORIOUS (Armour for Rikku)
MURASAME (Auron sword, One MP cost attachment)