It really depends on what "services" you are providing, but generally speaking you would be in violation of the Department of Treasury, Office of Foreign Assets Control (OFAC). These regulations are spelled out in 31 CFR §560.205 and 560.420 and apply to US citizens and residents wherever located.
Specifically, the action that is prohibited is the "exportation, reexportation, sale or supply of goods, technology, or services to Iran. Here "Services" is broadly construed to mean anything of value even if no money is exchanged, including providing technical assistance to an Iranian national or Iranian institution. See See § 560.204; §560.410.
The civil penalty for violation of these sanctions would be $250,000 or an amount "equal to twice the amount that is the basis of the violation". Criminal penalties may include fines up to $1 million and 20 years in prison.
Now there are some exempt transactions outlined by § 560.210 (c) which may be applicable here, however it would be up to you to prove that these are "information or informational materials" as defined by § 560.315.
For more information, 31 CFR Part 560, Subpart B refers to the prohibited transactions with Iran. Since you are not specifically spelling out what services you intend to provide, it is difficult to say for sure you would be in violation of them.
It should be noted though that the US Government uses publicly funded money to run a proxy server through which Iranians can access otherwise blocked websites such as social media in Iran.
