I thought this article from Nature News would be of particular interest to all of us. Please notice the online petition for his release.
Nature News article: Missing physicist (Omid Kokabee) may have been jailed in IranColleagues call for release of University of Texas graduate student.
The address is:http://www.nature.com/news/2011/110516/full/news.2011.291.html
Copy of the article is here also.