The event will take place today (Feb.18) at 17:00 local time in Japan. You can check the time here. However, the event will be held one hour from this article is being posted, just for reference.
Sony Computer Entertainment Japan president Hiroshi Kawano will be the one presenting the show. Furthermore, the show will have certain parts age restricted, possibly due to violent games.
The streaming is done via Ustream, you can watch it below: