B&H is accepting Canon EF 70-300mm f/4-5.6L IS USM Lens preorders.
This historically means that the lens will be available very soon - and that you will receive a lens out of the first shipment if you preorder from B&H now.
The Canon EF 70-300mm f/4-5.6 IS L USM Lens Review page is currently a hands-on preview of this new lens.