www.navand.ir provides such services.
You should contact them for more detail.

Atieh Dade Pardaz is another Sms provider. And here is the company's website: http://www.adpdigital.com/

Have you tried "Aatiye Daade Pardaaz"?
I know some friends over there, thus if you like I will be able to find their contact info.

About ADP, I should say that the company s great in this field but just like Rahyab and Magfa, they want me to guarantee a 10000 or such sms  per month  in the contract. The exact thing I need is some small packae of sms(for example 500 or 1000 in a month) to service  my cumtomers in my small e-business. But thank U 2 for information about ADP.
And about Navand!
I had not heard about the company before Ali introduced them to me. I browsed the web  site and saw that. I couldn't find any contact info so I mailed them on info@...
The reply came with contact details and I called them this morning.
The result was great. They're the exact thing I was waiting for all these months!!! They will send me the contract and other things needed. The most important thing for me was the several sms service packages they have prepared. I could choose the one I wanted from some 11 packages will several sms numbers and expiration times. So thanks again Ali for the info.
I believe that they will go on.

Could you please give me their contact information?

You can use CS Networks Web2SMS service. You can also send Bulk SMS messages.
It is really cheap and easy to use.

I am using it.

They will ask you about the amount of messages you are sending on monthly basis.
Ask them at: support@cs-networks.net

Regards