According to the post, the guitar/bass controller in Rock Band will feature ten buttons -- five at the top of the neck and five near the body. The new buttons will be used during designated solo sections using only hammer-ons and pull-offs (i.e. no strumming). A five-way switch will let you switch between special effects that you can purchase in-game. The Xplorer 360 guitars will still reportedly work with the game, however.
The microphone is said to work as a tambourine for parts of a song where no vocals are present, and a phoneme detector is meant to judge whether or not you're singing close to the right words. The drums are described as a set of four colored pads with a stand and a kick pedal, ready to be struck with real drum sticks. Also listed in the NeoGAF post are details on how multiplayer will work and descriptions of the in-progress visuals. If that's music to your ears, you might want to go and suggest some songs to be included in the final game at Rock Band's website.