You can watch it right here, and it starts some time today:
Streaming video by Ustream
Considering it’s at 12 o’clock today UK time, you don’t have much time to tune in and start watching. It’ll mainly cover the 3DS, although Wii U info isn’t completely impossible as well.
So yes, get watching people!
http://www.nintendo.co.jp/nintendo_direct/index.html
Source:
http://nintendo3dsdaily.com/nintendo3dsnews/so-theres-a-nintendo-direct-presentation-right-now/