Hi,

You would need to see if the software in question requires export controls. Either way, I believe the Department of Commerce is going to be your best bet.

The department of commerce has a department called the Bureau of Industry and Security. There's a great deal of information on how one exports -some- kinds of software.
http://www.bis.doc.gov/

Specific documents that the BIS enforces are here:
http://www.access.gpo.gov/bis/ear/ear_data.html

If they don't fit into one of the BIS enforced categories, go back through department of commerce looking for trade regulations regarding Iran. I believe they would be the proper Bureau to enforce unlawful trade.

I've done this work for my employer, so I know just enough to cause trouble. IANAL, but the regulations are legible on the fourth or fifth read-through.