There is a really cool site that keeps the updates of sales from each company. Sony, Microsoft and Nintendo. The sales that each of their next gen consoles has made. Good stuff.
Xbox 360 is around 10,000,000
Song PS3 is around 1,000,000
Nintendo is around 4,000,000

Good for Nintendo since is hasn't been out for so long. Xbox should have more than the others because it has been out for a year. The site is called nextgenwars.com you can type it into Google search engine and it should be the first find. Enjoy!