Automatic conversion between .ps to .pdf upon download onto Mac OSX?

Is there any way to convert .ps to .pdf every time automatically as a .ps is downloaded onto a Mac machine? (Using Mountain Lion 10.8) - can Automator perform this task? - convert and then delete the .ps It's annoying that it has to convert from .ps to .pdf in preview every time I open the file, and quick preview doesn't work on .ps.