According to the site's listings overnight - and still this morning - MGS: Rising is down for PC, PS3 and Xbox 360, with "TBA" listed for launch dates.
However, the site is more specific about a new PSP game, Metal Gear Solid: Peace Walker, which is lists for 2010. Double oops. Mind you, Sony still has them beaten on that front after outing the PSP Go including a new MGS game over the weekend on its own prematurely published online TV show.
We still expect to hear about the new MGS PSP game - Peace Walker, then - at the Sony conference tonight at 11am PST / 7pm BST / 8pm CET, although given MGS: Rising's presence at the Microsoft conference yesterday we wouldn't necessarily expect to hear about that again until Konami itself pipes up.