It has been confirmed that Nintendo will reveal Wii U sales information during tomorrow's European Nintendo Direct broadcast and during their live press event in NYC. Although it was widely expected, Nintendo President Saturo Iwata tweeted the brief details of what the presentations will consist of.
"Good evening, it's Iwata from Nintendo. Tomorrow at 4pm [Japanese time] we'll broadcast online the Wii U's sale information," Iwata said (via). "We'll tell you when the Wii U will launch and how much for."
Nintendo of America's press conference will be held on September 13 at 10:00am EDT in New YorkCity. At the same time, Nintendo of Europe will be holding a Nintendo Direct presentation at 4:00pm CET. For those who want to tune in, Nintendo will be streaming the broadcast on their site.