BioZ

Hello, I've just been gifted a ProMedia Ultra 5.1 system, and I have questions: Is this system only to be connected to a PC with sound card? Was it intended to be a desktop-based sound system, or could it be used in some other way? Could it run from an iPad, iPhone or iMac? I see that the speakers are 4 Ohm; could they be used separately from the control unit? I am a newbie to home theater/surround systems, having happily existed for some time on NAD and PSB products from the last century. Enlighten me, please. (Photo of system below, courtesy Klipsch Web site)