i doubt any home console will pass the PS2 in terms of marketshare for a long time. However the Wii does still have a chance of outselling the PS2, though even if it does happen it won't be for another 3-4 years seeing as the PS2 is looking likely to pass the 150 million shipped mark over the next few years.
As for the DS -- it will pass the PS2 in hardware and marketshare, but it is in a very different market. Most families will only have 1 home console, while many will have multiple handhelds.