IGN Wii has an interview with Red Octane about the upcoming Guitar Hero III for Wii:

While the development team is still exploring innovative ways to use the remote, Kai Huang told us: “We are really excited about the Wii game because there are so many options for the Wii remote. However, you will play the game with a guitar peripheral and it will be similar to a guitar you’ve seen in the past.”

He also confirmed that Guitar Hero III on Wii contains features included in other versions of the upcoming game – such as online play and downloadable music.

Wow, sounds pretty cool!   Especially being able to use online play and downloadable music!

Source: IGN Wii