(Parts 1-4 of this coverage series can be found here, here, here, and here.)

United States: The Office of Management and Budget today directed all federal agencies to bar employees from accessing the Wikileaks web site. Talking Points Memo obtained a copy of letter sent out by OMB, which "directed the agencies to immediately tell their employees to 'safeguard classified information' by not accessing Wikileaks over the Internet.

Classified information, the OMB notes, 'remains classified ... until it is declassified by an appropriate U.S. Government authority.' Employees may not view classified info over a non-classified system (i.e., the Internet), the OMB says, 'as doing so risks that material still classified will be placed onto non-classified systems.'"
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AFP, The Guardian and CNN have more on the story.

Update 1: Gawker reports that "U.S. soldiers in Iraq who try to read about the Wikileaks disclosures—or read coverage of them in mainstream news sites—on unclassified networks get a page warning them that they're about to break the law.[...]

A tipster wrote to tell us that 'the Army's unclassified, NIPRNET network in Iraq has blocked every major news website because of the Wikileaks issue,' going on to say that Foxnews.com, CNN.com, MSNBC.com, the Huffington Post, and a variety of other sites are blocked on the Army's unclassified network."

Update 2: US corporations are getting in on the censorship game too. We are informed that HP sent out a letter to all employees warning them not to visits the WikiLeaks website. Will HP censor The New York Times as well?

Canada: The Montreal Gazette reports that "Defence Department staff have been warned against using government computers to sift through secret documents released by WikiLeaks. An email dubbed 'Wikileaks Notice' in the subject line says military computers are 'not to be used to visit the Wikileaks site or any other websites containing such information.'"

Update 3: Australia: We were also informed that a letter was sent out on the Australian defence network yesterday, warning employees not to access WikiLeaks, which would be considered a security breach.