The boxart for the Wii version of Samba de Amigo has now been revealed in tiny form on Gamestop's site. It is, as far as we know, the first game to feature the new red Nintendo Wi-Fi Connection Pay-to-Play logo, which was first shown at GDC this year.
Either this means that you'll have to pay a subscription fee to play Samba online, or (infinitely more likely) that downloadable songs will be available over Nintendo Wi-Fi Connection. Which, if true, makes the Wii version of Rock Band (with its new lineup of expansion discs!) just that much more insulting.