How can I mount speakers on drywall?

I have the Logitech Z-5500 sound system and I want to mount the speakers on sheet rock without requiring awkward placement in studs? I’m afraid if I just screw them up they will fall off the wall easily with loud music.

Are there special screws for dry wall? I know that when I put wall jacks in for networking the boxes have a tab that keep it from falling back out. Are there special screws that handle this?