So far, there have been 10 Links in the span of the series.
Link #1 is the one we know from the first two games in the series. He is known as the Hero of Hyrule.
Link #2 is the one that debuted in A Link to the Past. As stated above, he was also in Link's Awakening, the Oracle games, and is now in this upcoming 3DS title. He is known as the Hero of Legend and the Hero of the Essences of Time and Nature.
Link #3 is the one that debuted in Ocarina of Time. He also appeared in Majora's Mask and Twilight Princess (or at least his spirit, inside the Hero's Shade). He is known as the Hero of Time.
Link #4 is the one from Four Swords (no, he and the Four Sword Adventures Link are not the same). He does not have a title.
Link #5 is the one we refer to as "Toon Link". He was in Wind Waker and Phantom Hourglass. He is known as the Hero of Winds.
Link #6 is the one from Four Sword Adventures. He is known as the Hero of Light.
Link #7 is the one from Minish Cap. He is known as the Hero of Men.
Link #8 is the one from Twilight Princess. He is known as the Hero Chosen by the Gods.
Link #9 is the one from Spirit Tracks. It is unknown if he is a descendant of "Toon Link" like how the Zelda of that game is the descendant of "Toon Zelda"/Tetra. He is known as the Royal Engineer.
Link #10 is the one from Skyward Sword. He is the first Link in the timeline, but not the first Link (The first Link is the one that served Hylia). He is known as the Chosen Hero or the Chosen Knight of the Goddess.
Crazy, huh?