Tweets:
Streams:
UK Stream (11 AM GMT): http://www.nintendo.co.uk/Misc-/Nintendo-Direct/Latest-Nintendo-Direct/Nintendo-Direct-698557.html
Japan Stream (20:00 JST): http://www.nintendo.co.jp/pokemon/direct20130108/index.html
Updates:
EDIT: On the announcement page ( http://www.pokemon.co.jp/ex/important_announce/?a001=msign ) there's a countdown. Warning: the countdown is based on the time on your computer.
Direct Screenshots:
Will update with links as they come.
Credit to Andrefpvs for the pics.