Can mask be used on PS like on PSP and how is it done?

not sure how a mask is invoked in PSP, but you can create a "quick mask" by clicking the little ICON in the bottom of the Layers palette.

just remember that painting with black increases the masked area; painting with white increases the selected area and painting with gray or another color creates a semi-transparent area, useful for feathering or anti-aliased effects.

hope that helps,
:)
retrocity

Thanks retrocity. :)