While the new Nintendo  DSi is not exactly a completely next-gen
'DS2',   it is more than just a model revision of DS, like the DS Lite
was.

The main thing that's most striking is that both of the screens in DSi
are -touch- screens, unlike with DS and DS Lite which only have one
touch screen.

That means DSi will have its own software that cannot be played on DS
or DS Lite.

DSi will be backward compatible with DS games, but will lack the GBA
slot.

Both DSi screens are also slightly larger, 3.25 inches,
compared to 3.0 inches of DS & DS Lite.

IGN posted full specs here: http://ds.ign.com/articles/915/915510p1.html

This is bound to be confusing for many people. I still don't fully
understand this move by Nintendo.

I suppose this can be comparable to Nintendo moving from GameBoy
(and GameBoy Pocket and any of the other b&w models) to GameBoy Color.
A stop-gap before GBA was released,  so therefore I still expect a
true DS2 to come out in a few more years.