Nintendo President, Satoru Iwata, made an interesting tweet today about launch info for Japan at the September 13 Wii U event in NYC:

「９月に任天堂のカンファレンスがある」と予想されている方が少なからずいらっしゃるようです。日本でのWii Uの発表は、カンファレンス以外の方法で行う予定であることを、あらかじめお知らせいたします。 – Iwata

Translation according to Neogaf: “There are more than a few people who are thinking, ‘There’ll be a Nintendo Conference in September.’ I want to tell you in advance that the announcement of the Wii U in Japan is planned in a way not involving the Conference.”

This probably just means that there will be another Nintendo Direct or another event for Japan’s info.  My guess is the US will still get all the Wii U launch info on the 13th and probably a whole showcase of the launch lineup as well.