I thought before I get asked to do it, I should also get the Prismacolor-style colour swatch for Corel Painter IX and X users up and posted. (This should help those who are trying to emulate felts or artpens.)
1. Unzip the .colors file.
2. Place the colors file in the Color Sets subfolder. In Windows, you can find the Color Sets subfolder where the Painter X or IX is stored. (I am not sure where you'd find it for Mac users but I suspect it is similar.)