Link is right-handed in Skyward Sword and he's staying that way.
Despite rumors to the contrary, Legend of Zelda: Skyward Sword will not feature a left-handed mode, meaning that southpaw players are going to have to get used to sword fighting right-handed, not unlike in the Wii version of Twilight Princess.
There was confusion surrounding the existence of a left-handed mode in Skyward Sword, thanks in no small part to a video report by IGN, which said that it was an option players could pick when they started playing the game. This information was seemingly false, however, with Nintendo confirming the game's right-handedness to Kotaku's Stephen Totilo.
Traditionally, Link has been left-handed in most of his major adventures, and was originally supposed to be in Twilight Princess as well. However, Nintendo reversed it on the Wii so that Link's sword was in the same hand as the player was holding the Wii-mote. It's a shame that Nintendo didn't apply that same line of thinking for left-handed players in Skyward Sword, especially when you consider the controls are a lot more sensitive. Fortunately, the game is reportedly very playable for left-handed gamers, even if getting used to it does take a little while.
Legend of Zelda: Skyward Sword comes out for the Wii on November 20th.