Slingshot

The slingshot is a basic ranged weapon found in a couple of Zelda games. Its not particulary powerful and is replaced fairly quickly by the Bow.

Ocarina of Time

Found in the Great Deku Tree, can hold 30 seeds, using it puts you in a first person perspective, all shots arc downwards after traveling a while. You can get a sack pouch capable of holding 40 in the Lost Woods if you shoot the bulls-eye on the 'target' of the tree on the way to Saria, it has a Deku Scrub sitting on top of the tree in its hole. You can acquire the 50 seed sack at the shooting gallery in Castle Town.

Twilight Princess

You buy this at the item shop in Ordon Village, it comes with 50 seeds and the capacity to carry more is never increased. Functions the same way as the Bow in Twilight Princess, except that it arcs downward after a while.

Skyward Sword

You obtain the Slingshot after finding Kikwi leader's friends. Unlike the Bow and Arrow, the Slingshot only requires players to point and shoot with the Wiimote, so the Slingshot isn't too different from the Twilight Princess version. Link will simply take aim and shoot. This allows Link to fire at enemies quickly in battle when he can't take the time to aim with the Bow, due to its aiming mechanism.