Here is the situation on the three detained American hikers in a nutshell:
Shane Bauer, Josh Fattal and Sarah Shourd have been detained in Iran since July 31, 2009, when news reports say they accidentally crossed an unmarked border during a hiking trip in the mountains of Iraqi Kurdistan. They were in a peaceful region of Iraq that is increasingly popular with Western tourists.
The three young Americans, all graduates of the University of California at Berkeley, are believed to be held in the Iranian capital, Tehran. They have had no contact with their families, and have not been granted their right to consular access.
I just signed the online petition requesting that the Iranian government release the detained hikers.
I strongly urge you to do the same. The site also lists other supportive actions you can take.