The fact we can even ask this question is something really great, after all those years (10 years!!) we were all waiting for Fallout 3 and situation looked so desperate many times that there will never be any new "real" Fallout. Fortunatelly, Fallout 3 was huge success, so it was no big surprise that Bethesda announced Fallout 4 even before release of Fallout 3. Fact is that nobody really knows exact date of release of Fallout 4, but according to executive producer of Fallout 3 Todd Howard three years are a good span of time between sequels of game, so we can hope that we will all be playing Fallout 4 in 2011 or 2012. It is still long time, but hell, it is much better then ten years between Fallout 2 and Fallout 3.