Nikon announced new versions of the 300mm f/2.8G VR lens and the TC-20E teleconverter today. Both will be available very late next month (essentially at the end of the January).
The 300mm lens gets the newer VR seen in the 70-200mm update (known as VRII) and some optimisations for focus performance. A new A/M mode on the focus switch (not to be confused [!] with the M/A mode) offers a more secure return to autofocus from tweaked manual focus for those that move between the two types of focus. Cost of the new lens is US$5899.
The new teleconverter is said to be the first that uses aspherical elements. This is done in an attempt to improve corner performance, especially coma and abberations. Rubber seals at the mount also improve its weathersealing. Finally, the end caps have been redesigned (finally!). The TC-20E III will sell for US$499.