The parts required for a PostScript font on the PC are the .pfm and matching .pfb files. Those are the screen and outline font pair for a given typface.
The .afm file is useless to anyone unless you are using FontLab, Fontographer or other font editor to alter a font. That way you are certain to use the same kerning, leading and other font metric settings Adobe (or other font creator) used when editing and saving your changes. Otherwise, they have no use. Having .afm files on your Mac or PC does nothing to the fonts themselves. Delete or leave them as you see fit.
Beyond that, crismar, the fonts you have from the PC will not work in any way, shape or form until you either replace them with identical Mac versions, or convert the ones you have to Mac format. FontForge, as mentioned, is one that can do that. As will
TransType.