Hideo Kojima Will Focus On Metal Gear Solid: Peace Walker.

He'll take a backset on the game's development, instead focusing his attention on the PSP's Metal Gear Solid: Peace Walker.
"We're creating Rising with Kojima Productions' up-and-coming young bloods, because the game is for the young bloods as well, a new experience,” said Kojima, who added that Rising would still take the form of “a stealth espionage action game, of course".</blockquote>

Kojima has described Peace Walker as the "true" Metal Gear Solid sequel to the franchise:
"This is what I mean by a true sequel - it means that I'm writing the script, I'm doing the game direction, I'm working on the title full-time and the main team of Metal Gear Solid 4 is working on this title," he said.</blockquote>

Metal Gear Solid: Peace Walker is due out next year exclusively on the PSP.