As far as I know, there is no independent press to speak of at all in Libya, Saudi Arabia, and Tunisia, whereas there exist many in Iran, in print and online, some of which you can read if you can read Farsi: e.g., <http://www.zanan.co.ir/>.
As for jail time, many other countries in the Middle East, as well as elsewhere, jail more journalists than Iran, as you can see <http://www.rsf.org/article.php3?id_article=16088> <http://www.rsf.org/rubrique.php3?id_rubrique=116>.
Only following Washington's priority can one believe that Iran is the worst place for journalism in the Middle East or the fourth worst place in the world.
-- Yoshie
I am well over my three a day quota so this is the last you will hear from me today on this subject.
Here is what RSF says about independent press freedom of these countries: (including Iran) "The governments of Libya, Iran, Syria, Tunisia and Saudi Arabia have total control over news within their borders and are among the world's most repressive regimes. All are ruled by men who deeply distrust the independent media and freely crack down on dissenting voices." http://www.rsf.org/rubrique.php3?id_rubrique=579
"Iran is still the region's biggest prison for journalists. At the end of the year, five were in jail there, including the best-known, Akbar Ganji. Pressure by the international community and human rights organisations have often called for his release, in vain. The accession of hardliner Mahmoud Ahmadinejad to the presidency on 3 August did not make things easier and the last quarter of the year was especially repressive, with at least 32 newspapers suspended."
So I take it they downgraded Iran's status due to total press censorship, press suspension, and major jail time as a little incentive as they say to keep journalists in line. Also by the way the countries you mentioned are all fairly close: Tunisa--147, Saudia Arabia-154, Libya-162 and Iran--164.
Does this sound like a better deal for press freedom if you live in Tunisa rather than Iran? Sounds all about the same to me. Pretty harsh.