Yes they do, you can find it at Game Stop and buy it there as a used version. Brand new Windwaker disks are hard to come by and are quite expensive.
Now that the new Windwaker HD is out, you can find the new version at most electronic retailers (Futureshop, Bestbuy, Walmart) or on the Nintendo eShop to download the digital copy.
They have remade the Legend of Zelda: The Wind Waker for the Wii U in HD graphics.
In the accepted Zelda timeline, Phantom Hourglass is after Wind Waker. When talking about release dates, Four Swords Adventures is after Wind Waker.
A Few
no
wind waker
no
nothing
No, Link will not age in this game
Nintendo Eshop for $49.99
Wind Waker
yes there is for the Game Cube
Yes, a remake of The Legend of Zelda: the Wind Waker will be coming to Wii U, in October 2013.