Hot on the heels of Sony's big Press event on the PS4, users over at NeoGAF Forums have discovered that Eventcore (formerly ustechs) registered the Domain xboxevent.com yesterday (February 21th).
According to NeoGAF, "Eventcore plans and executes large events and meetings like 2013 AT&T developer summit (http://www.whois.com/whois/2013devsummit.com) and they only acquire domains for events they are organizing. https://www.eventcore.com/
This is not terribly surprising, as few expected Microsoft to sit back and let Sony steal the spotlight prior to E3 2013. CVG reported that "It is said that Microsoft will now showcase its console at a one-off media event in early April - though it is expected that discussion about future tech would be an inevitability if Microsoft engineers and developers attend GDC in March" We will see soon Enough... Keep your eyes open.