I got this fact from a news site, take a look this article:

"The hardcore gamer’s top PS2 title of 2005, Shadow of the Colossus, is strongly rumoured to be in development for PS3. Whilst European gamers wait patiently for the early 2006 release of Shadow of the Colossus on the PS2, Internet forums are alight today with eager gamers discussing a rumor that US magazine EGM has published, stating that the developers of what is surely a strong candidate for 2005’s game of the year, are already at work on the PS3 version. "

I have Shadow Of The Colossus on my PS2, and I already wonder what it would look like running on the PS3, allthough I doubt the rumours are true.