Games Like Fallout 3 for PS2?

Now I want to play fallout 3 real bad. I don't have a PS3 or XBOX though. My compy's ancient. Is there any games for the PS2 that are like fallout 3. An action game with an open and explorable world. Maybe some light RPG elements, but I mainly want exploration. (I also have a Wii, but that has no open world rpg/action games.) Are there any games like that? Thanks.