Well, you know, it's actually true that a high atmospheric nuclear explosion WILL burn out any unhardened circuits via a surge of power. Anything that can transmit electricity will be affected. A 120-mile high burst centered above Nebraska will create an EMP cone covering the entire continental US, most of the lower half of Canada and most of Mexico. The EMP needs a direct line of sight and travels at the speed of light (IIRC). It will also disrupt the ionosphere for a while, wrecking radar and radio.
The problem Iran, or anyone else faces is most military systems are protected from EMP. The same thing goes for power plants (especially nuclear) and the major fiber-based telecom networks. The redundancy of the internet and it's backbones will allow it to continue, virtually unchanged.
The most serious effect of an EMP will be the civilian population. While our homes will have power within 72 hours tops; we won't have any electrical applicance that will actually work. All our TVs, radios, computers, cars and so forth won't be working and will need new circuits.
The best way to preserve some of our essential electronic equipment would be to wrap certain items in aluminum foil and place them within Faraday Cages. This will reroute the EMP around the exterior of the cage, leaving all items inside, perfectly safe.
I suspect shipping containers would be equally effective in shielding electronic equipment from the effects of an EMP. So, the best place to obtain unaffected electronics would be at the docks or wherever a container was kept closed.
I'm thinkin' that this would be my chance to get that 50" plasma HDTV that my wife keeps vetoing...