Well not "here" as in "your home or electronics retail outlet" but "here" as in "exists in at least one product". According to Engadget NEC's xHCI host controller is now the first certified product to use USB 3.0. Jeff Ravencraft, president of USB-IF (the group that oversaw the certification) said that he expects the first USB 3.0 end products to be in stores early 2010.

Ravencraft also let slip that he believed some manufacturers will likely have products in stores before Christmas of 2009. That said, there's a bit of a caveat coming. USB 3.0 is not FULLY compatible with USB 2.0 cables and the like. If you have a USB 3.0 gadget connected to a USB 3.0 receptor port with a USB 2.0 cable, you'll only be able to transfer at 2.0 speeds.

To be honest, I think that's kind of awesome. Despite the fact that they use totally different cables, USB 3.0 will be backwards compatible to all earlier devices and connectors. That's good news for both early, and late adopters.