The USA Today has re-published a story it ran last week that stated the Wii version of Rock band 2 will not have the same online and song downloading capabilities as the Xbox 360 and PS3 versions. Apparently the USA Today was contacted by Harmonix and updated on the game's status.
"while "unannounced," MTV games has confirmed that Rock Band 2 for the Wii will "offer the same online functionality -- i.e. song downloads and Internet multiplayer modes -- as the Microsoft Xbox 360 and Sony PS3 versions."
Good to hear if you were considering picking RB2 up for the Wii.