It will be bundled however for Xbox 360 and Wii. This "does not affect" European customers. It's all down to "agreement terms" for North America.
If you've already pre-ordered a PS3 version bundled with the keyboard then MTV Games will be working to ensure those are honoured but otherwise it's going to be completely unavailable. You can of course buy the two separately costing an extra $10.
Here's what studiohad to say:
"You may have seen that retailers have taken down the Rock Band 3 keyboard/software bundle pre-orders for PlayStation 3. Unfortunately, this SKU will not be available in the U.S. (including Canada and Mexico) due to the agreement terms for the region."
"However, Mad Catz and MTV Games are working with those retailers that accepted pre-orders to enable them, if they choose, to honor those pre-orders placed prior to this change as soft bundles (separate discs and keyboards), at pre-order pricing. These retailers will have more details shortly."
It's odd why PlayStation 3 has been singled out and given the cold shoulder. The keyboard is the only new addition to Rock Band 3 instrument wise as previous guitar and drum kit peripherals will all work fine. Europe can bundle its heart out at least.
Rock Band 3 releases on Xbox 360, PS3, Wii and DS October 26th in the US.