Wii downloads sites are available on the internet for a very long time...
Here is a quick review about some:
Wii Downloads - The best review site for Wii Downloads, 3 sites for wii games, movies, homebrew stuff to unlock and more. The site sums up all the goods you will get when you join a downloads site (like the one below), and the downlod speed. Wii Downloads at it's best.
Wii Downloads - Another review site for Wii Downloads, a bit messy but easy to the eyes.
Wii Downloads - A good Wii Downloads site with all the goods every wii owner must have!
Before you join a wii downloads site read Wii Downloads, they have an important information and tips for wii.
Good Luck.
