The new Olympus M.Zuiko Digital ED 300mm f/4 IS PRO ($2,499) and Fujinon XF 100-400mm f/4.5-5.6 R LM OIS WR ($1,899.95) lenses are now shipping in the US in limited quantities.
The Olympus 300 f/4 is scheduled to be in stock on February 25th while Fuji 100-400 should be available in stock on February 22nd:
Via Fujiaddict