I got this from Facebook, I dunno if it really works, it was on a guy I went to school with's profile!
if you use Twitter, set your location to Tehran & your time zone to GMT +3.30. Iranian security forces are hunting for bloggers using location/timezone searches. The more people at this location, the more of a logjam it creates for forces trying to shut down Iranians' access to the internet. Cut & paste & pass it on.