According to Wikipedia: In 2010, the film will be re-released in the Disney Digital 3-D format, with a DVD / Blu-Ray re-release followed.
From the page as well: Disney has recently announced that a home video re-release is planned in 2010 after the release of the 3-D version which will bring the film to DVD and, for the first time, on Blu-Ray.
So it seems we will see some advertisements in 2009 for this new 3D version, and both 3D and classic version will be simultaneously offered on DVD/Blu-ray in 2009/2010.