Pikmin 3 may be a Wii game.
In 2003 Miyamoto said in an interview he already had the basic premise for Pikmin 3[1]
Cubed 3 news ran an April fools joke in 2006 stating that Pikmin 3 would be a launch title for the Revolution (Wii)[2]
Later in April Spong news asserted that according to its press contacts Pikmin 3 would appear on the Wii at some point (probably some time after the launch) [3]
Officially Nintendo are yet to announce a sequel however they have hinted at their desire to create one in an interview on Pikmin 2 [4]