According to the article, some agencies other than NASA using Twitter include:
NIH - health related dispatches
US Geological Survey - earthquake & tsunmai warnings
FDA - updates on food recalls
You can find all of this and more on Steve Luncefords's Twitter directory GovTwit...
See excerpt from article below -
Last fall, seeing a growing number of individuals from the federal community Twittering, BearingPoint public relations executive Steve Lunceford started a directory, called GovTwit, of their Twitter names and affiliations.
"It took me a little convincing to see that people were using this for a little more than 'I just ate a hot dog.' But once I started using Twitter, I found some really interesting folks to start following," he said. There were "a number of rich conversations going on in the government space."
The page debuted with 150 names. Now it has more than 1,000.
Agency public affairs departments have taken to using Twitter to spread public announcements, though the service is also frequently used by individuals within an agency, too. "They are not always speaking on behalf of their agency, [but] they are still having a lot of meaningful conversations," Lunceford said.
"You have some really valuable conversations — we did this at our agency, and here is how we crossed this barrier — those types of conversations are very valuable," Lunceford said.
Steve Ressler, who runs the popular GovLoop government-oriented social-networking site, has found that an increasing number of GovLoop members are using Twitter to talk about their activities.