The Wooden Sword is an item that has appeared in The Legend of Zelda series. It first appeared in The Legend of Zelda, where it was the first sword that Link could obtain. In the game it isn't very powerful, though until you find the White Sword you'll have to manage with it. In the aforementioned game, you'll find the wooden sword in one of the first caves.
It later appeared in the Wii and GameCube video game The Legend of Zelda: Twilight Princess, where it was also the first sword that Link would obtain. Prior to receiving the sword, Link has been sword training with Rusl, and soon into the game Rusl will drop by a treasure chest to Link's house containing the wooden sword. Soon later, Link will give the sword to Talo so that he will be able to get past him. Thankfully though, Link will later find a more powerful sword - the Ordon Sword.
Later on in the game, while in his wolf form, Link will come across the sword while searching for the kidnapped children. With this he is able to pick up their scent and save them.