Konami announced today that Metal Gear Solid: Peace Walker will not only be released on UMD but also digitally on the PlayStation Store. It will be released simultaneously with the UMD version April 29th in Japan. Those that are stuck with a PSPGo should rejoice as they can play this game, unlike Square-Enix’s Kingdom Hearts: Birth by Sleep, which is still UMD only.
The digital distribution of Metal Gear Solid: Peace Walker only applies to Japan. We are waiting for confirmation from Konami of America, to see if Peace Walker will be released simultaneously on the PlayStation Store in North America as well.