The Legend of Zelda: Ocarina of Time Game Guide

Great Fairy Fountains [GrtFary]

There are a multitude of Great Fairy Fountains in the game.  These house the
Great Fairy, who is summoned by playing Zelda's Lullaby on the Triforce mark in 
front of the Fountain.  These Great Fairies give you new magic abilities that 
you can use throughout your adventure.  Oh, and be sure to wear goggles before 
seeing these Fairies.....>_<

Great Fairy of Power

Located at: Death Mountain Trail's summit.  Bomb the discolored wall here to
unveil the entrance to this Great Fairy's Fountain.

Ability given: Advanced Spin Attack

Details: To use the Advanced Spin Attack, hold B until your sword glows yellow,
then release to spin around and release an energy wave that spans a long
length, at the cost of magic.  She also gives you the magic meter so you can
use the Great Fairies' powers, among other magic-consuming items.
Great Fairy of Magic #1

Located at: Hyrule Castle Grounds.  Pass the gate, then bomb the boulder in the
corner to reveal a crawlspace leading to this Great Fairy Fountain.

Ability given: Din's Fire

Details: Din's Fire is a C item.  Once used, Link pounds the ground with his
fist, releasing a wave of fire in all directions.  Very useful for crowd 
control and for lighting many things on fire in close quarters.
Great Fairy of Magic #2

Located at: Zora's Fountain.  There's an island behind Lord Jabu Jabu.  Plant a
bomb near the white rock to blow open the whole wall, revealing this Great 
Fairy Fountain.

Ability given: Farore's Wind

Details: Farore's Wind is a C item.  When first used, it creates a Warp Point.
Using it a second time will warp you to that point.  Realize that this can only 
be used inside dungeons with Dungeon Maps hidden inside.
Great Fairy of Magic #3

Located at: Death Mountain Crater.  After getting the Megaton Hammer, enter
Death Mountain Crater using the Goron City entrance.  Turn right, and break the
rocks with the hammer to reveal the entrance to this Great Fairy Fountain.

Ability given: Isn't an ability, per se, but is actually a magic meter upgrade.

Details: A magic meter upgrade.  It doubles your magic capacity, so you can use
more magic powers at one time.
Great Fairy of Magic #4

Located at: Desert Collosus.  Find the cracked wall between two palm trees and
bomb the wall to reveal the entrance to this fountain.

Ability given: Nayru's Love

Details: Protects Link for a few minutes at the expense of some serious magic
Great Fairy of Courage

Located at: Ganon's Castle.  After getting the Golden Gauntlets in the castle,
head to its grounds and lift the massive black stone out of the way.

Ability given: Isn't an ability, rather, it doubles your defense.

Details: Doubles your defense.  Now you can take twice the punishment you used
to.  This also outlines your hearts with white.