According to this, EA CEO John Riccitiello confirmed the existence of Rock Band for Wii in yesterday's investor conference call, following the release of the company's third quarter financials.
The CEO confirmd the rumoured existence of the game in a conference call, according to IGN, noting that EA "will, at some time, bring Rock Band to every [important] platform." For the Wii version, he noted: "I think the Wiimote is something that holds enormous promise."
Although no official announcement has been made, EA has confirmed that Riccitiello's remarks were true, and that players can expect to make sweet music on their Wiis sometime in the future.
A Wii version of Rockband was hnted at rather heavily on January 29 when the format was listed on the side of the game's new standalone microphone.