Question: Has anybody recently extended his visa in Tehran. I especially wonder how long it takes, don't mind waiting for a couple of hours in offices but hope that a "same day" extension is possible.
Answer: Iran visa extension is not a nightmare actually. In 1 or 2 days against paying about 10 or 20 dollars the visa can easily be extended in Tehran, Shiraz, Esfahan, Yazd and other touristy cities. Shiraz is the best place and has the most helpful staff. You should go to the immigration center in Kaveh street, Vali Asr Sq. and ask for an extension.
Check the cheapest Iran tours at http://www.uppersia.com/Iran-tours