While it's never been given an official, bells-and-whistles announcement by the company, they've made it clear enough in the past that Nintendo will some day release a Wii that's capable of playing DVDs.
It was meant to be in 2007, but that obviously didn't happen. Our advice is not to expect one in 2008, either, as Nintendo president Satoru Iwata has said "With supply constraints [of the Wii] continuing worldwide, the priority is on the current model".
The 0.3% of the population with a Wii but without a DVD player must surely be distraught.
Story source: kotaku.com [3].