Sony Japan will be holding a web presentation called "Game Heaven" on March 9th. During the presentation, new games will be announced for the Vita, new services and apps will be detailed, and there will be some talk from PlayStation Vita developers.
You can stream the presentation here. It's happening on March 9th and 3AM PST/6AM EST.
Last time Sony Japan streamed something online, it crashed nearly the entire time. And it's also wise to point out that it's likely only Japan-related announcements, otherwise Sony would have held the event during GDC next week.
Either way, there's bound to be something interesting coming out of the event.