The TIE Fighter-Wing looking "green" game cases have been out for Xbox 360 since most November releases. Go Nintendo has an image of what they'll look like for Wii games, beginning with Final Fantasy Crystal Chronicles: The Crystal Bearers.
As you can see, it keeps the octagonal design on the right side, but stamps out a recycling symbol on the left. I suppose the weights and material used are equivalent. All that's left now is a look at Sony's Blu-ray case design.
A larger version of this image, if you're interested, is at Go Nintendo's link.
New 'Green' Game Cases - Wii Version [Go Nintendo]