[Update: Err...gross price alert. Look at this: They want $29.99 apiece for these two!]
Konami said that a re-release of the PSP versions of Silent Hill: Shattered Memories and Silent Hill: Origins will come to the PlayStation Network soon. In Europe. They gave no release date, but did give a price of £7.99.
As for North America, no confirmation has come down the line. But I'm sure we'll see their release soon on our side, too.
I don't know why, but it seems like I'm the only one that truly dug Silent Hill: Shattered Memories. I played it on the Wii, which had me flailing about while screaming and running and place. Maybe that's what won me over.