I remember back before the Wii came out that people were talking about how poorly it was going to do because of its relatively low power in comparison to the other next-gen consoles. To the contrary, Nintendo seems to be doing just as good, if not better than ever.
The Wii in particular is doing awesome, last month it outsold both the PS3 and the Xbox 360 despite the fact that it is still hard to find on store shelves. The numbers come courtesy of NPD and show the 8 top-selling consoles. If you look at the list you'll see that half of those are Nintendo products.
The older hardware is still outselling the new hardware though, with the 2-year-old DS taking the number 1 spot on the list with over 508k sold. The aging PS2 took second-place with 280k, that's over twice as many sold as the PS3.
It looks like it's going to be a great year for Nintendo. Now if they could only do something about the Wii shortages, they could probably sell even more.