The Committee to Protect Bloggers is holding a day of protest tomorrow (February 22) over the imprisonment of Iranian bloggers Arash Sigarchi and Mojtaba Saminejad.
There is a successful precedent for such campaigns championing the Iranian blogosphere: the CPB reminds readers that Sina Motallebi, an Iranian journalist who was also imprisoned by the government, credited publicity of his plight with helping to secure his release.
If you want to start finding out about Iranian blogs, this Wikipedia page has an extensive list of links. Hossein Derakhshan, the man widely acknowledged as the "godfather" of the Iranian blogosphere, gave a talk at the Northern Voice blogging conference in Vancouver last week. Some notes from his talk - plus the other participants of the panel on the blogger as citizen journalist - are here.