News from Next-gen.com:

Activision predicts that the Wii will continue to dominate in 2008 selling somewhere over 6 million units.  The xbox360 will be second with somewhere between 4-5 million, while the PS3 stays behind at 3-4 million.

I think that the Wii will continue to do well, but perhaps they are giving the PS3 a little less credit than it deserves.  It is a very powerful system, and now with Blu-Ray winning the format war maybe things will pick up a bit for Sony.  Then again, Microsoft may adopt the format.  It will be an interesting year.  Glad to be a part of it.

Full article here: Wii 2008