For the majority of PS2 games capable of 480p, you simply hold down "triangle + x" as the game is booting. You will then recieve a message box which allows you to enable progressive scan.
In a few cases, however, progressive scan is an option in the menu. For Jak 2, you had to select progressive scan from the options menu. Considering that R&C uses essentially the same graphics engine, I have a feeling it will be the same. I believe it is in the options menu for R&C2 as well, so it should be the same here.