The days of only being able to buy Rock Band instruments in a gigantic pack are about to come to an end as the creators just announced dates and pricing on their instruments. The drums will be US$79 on February 12 and the guitar will be US$59 on April 1. The PlayStation 3 version of the guitar will work on both PS3 and PS2, and will also get the US$59 price tag. There's no announcement for the USB microphone, however, but you can rig up your own mic by using a standard USB mic or just the Xbox Live headset and a controller.
AU: Man, I'd just love it if we had a release date in Australia... Of course, I'm sure our good friends at Kotaku AU will update us when that happens.