GSA has completed the initial release of their new Social Media Registry. The idea is to provide a place where citizens can verify that a twitter, facebook or other account that appears to be from a government user really is from a government user. And is not some random person just pretending to be the government. The social media equivalent of producing your own badge and claiming to be from the FBI.
Not a bad idea actually (the social media registry, not the FBI badge thing). Still early days for the tool, but you can both registry and check on existing registrations on howto.gov.
In looking for this site I came across this from Expert Labs that keeps track of all the twitter account activity for the Feds. Actually kind of nice too.