Generally speaking you need to present your GMAT results, as well as TOEFL results, have some years of working experience, and you have to secure the funding for tuition and living costs.
Especially costs can be high in US, you can have a look at http://www.find-mba.com/usa/1 where you find a very good overview of US progr. including websites of the schools to get information about cost, but as well about admission conditions.
I can't give you information for other special requirements for US.

Inspite of the bad press Iran is getting, United States is a great learning place for Iranians. You can get a lot of information, a lot of schools have Iranian proffesors, such as IIT (Chicago) University Of Chicago, etc. Some of them are think tanks, but I am sure they can help you out. Your other source is the American consulate.
Yes, unfortunately US is not as hospitable as it was when I was a student, tuition was the least of our concern, we could work part time at the school or at some other places and get enough to pay for schools. Left with enough change to pay for dates etc. But if you are an Iranian male, you do not have to worry about dates, American College girls are crazy about Iranian guys, so they will pay for you. I used to envy all the Iranian guys at college as they got all the action. Not because you guys are cute, but a lot of them during my time lied a lot about being virgins, this, posed a challenge for the girls.
Anyway, USA has great schools for you and you will enjoy it.