Nintendo announced a Super Smash Bros. for Wii U bundle that includes a Gamecube controller and more importantly an adapter to plug Gamecube controllers into Wii U. This bundle, according to Amazon, will cost $99.99.
Nintendo has not set official pricing for the package and have not said if the Wii U Gamecube controller adapter will be sold separately.
Super Smash Bros. for Wii U will be released sometime in 2014. The Nintendo 3DS version is scheduled to come out on October 3 in North America. Siliconera has been playing Super Smash Bros. for Nintendo 3DS and will have impressions soon.