Screensaver .SCR files on MAC

I have a couple of cool screensavers (.scr files) which I have used on my PC in the past, which I want to use on my Mac. What do I have to do to make it work? Forgive my ignorance, I am new to the Mac world.

Thanks for any pointers.

iMac Intel 2.16 GHz 20" (Late 2006) Mac OS X (10.4.7)