Government (Canada)
Alberta Geological Survey http://twitter.com/geology4u

Government (UK)
Unofficial service of official news feeds from UK Government http://twitter.com/HMGOV
TellThemWhatYouThink.org http://twitter.com/govconsultation
CommunitiesUK http://twitter.com/CommunitiesUK
DIUS http://twitter.com/DIUS_Science
UK Foreign and Commonwealth Office http://twitter.com/foreignoffice

 

Government (US)
Arvada, CO http://twitter.com/cityofarvada
Austin, TX PD http://twitter.com/AustinPD (UPDATES PROTECTED)
Colorado http://twitter.com/coloradogov
Committee on Education and Labor, US House of Representatives/Rep. George Miller (D-CA) http://twitter.com/edlabordems
Franklin, MA PD http://twitter.com/franklinpolice (Needs more updates)
Hillsborough, NC http://twitter.com/Hillsborough
Commonwealth of Kentucky http://twitter.com/kygov
LAFD http://twitter.com/LAFD
Louisville, KY http://twitter.com/louisvillekygov
Maine (consumer alerts- inactive) http://twitter.com/www_maine_gov
NASA http://twitter.com/NASA
NASA: Mars http://twitter.com/MarsPhoenix
Nebraska http://explore.twitter.com/nebraskagov
Peoria, AZ http://twitter.com/PeoriaAZ
Public Laws (Signing Status) http://twitter.com/publiclaws (SOURCE?)
Republican Study Committee, US House of Representatives http://twitter.com/RSC
Rhode Island http://twitter.com/rigov
South Carolina http://twitter.com/scgov
U.S. Dept. of State (IIP) Print Publications http://twitter.com/Americagovprint
US House of Representatives (Floor Vote) http://twitter.com/HouseFloor
US Senate (Floor Vote) http://twitter.com/SenateFloor
USAgov http://twitter.com/USAgov
Utah http://twitter.com/UtahGov
Vermont http://twitter.com/vermontgov
Virginia Beach, VA – http://twitter.com/CityofVaBeach
The White House http://twitter.com/TheWhiteHouse
WomensHealth.gov http://twitter.com/womenshealth

 

Government (US) - Regional
Hampton Roads Planning District Commission (HR Green) www.twitter.com/HRGreen

 

 

Political Action Committies
Democratic Congressional Campaign Committee http://twitter.com/dccc
National Republican Congressional Committee http://twitter.com/NRCC
National Republican Senatorial Committee http://twitter.com/NRSC

 

Political/Human Rights
Free Burma http://twitter.com/FreeBurma

Students for a Free Tibet http://twitter.com/teamtibet

 

 

Politicians/Elected Officials (UK)
Lynn Featherstone (MP) http://twitter.com/lfeatherstone
The Office of Prime Minister Gordon Brown http://twitter.com/DowningStreet
Tom Watson (MP) http://twitter.com/tom_watson

 

Politicians/Elected Officials (US)
Mayor Mark Begich (D-Anchorage, AK) http://twitter.com/MarkBegich
Representative John Boehner (R-OH) http://twitter.com/johnboehner
Mayor Mark Boughton (R-Danbury, CT) http://twitter.com/MayorMark
Representative Roy Blunt (R-MO) http://twitter.com/RoyBlunt
Representative Eric Cantor (R-VA) http://twitter.com/EricCantor
Lt. Governor John Cherry (D-MI) http://twitter.com/johncherry
Sen. Hillary Clinton (D-NY) http://twitter.com/Hillary2008 (Official Twitter?)
Representative John Culberson (R-TX) http://twitter.com/johnculberson
Governor Jennifer Granholm (D-MI) http://twitter.com/govgranholm
Representative Pete Hoekstra (R-MI) http://twitter.com/petehoekstra
Sen. Jim Inhofe (R-OK) http://twitter.com/jiminhofe
Representative Randy Kuhl (R-NY) http://twitter.com/RandyKuhl
Sen. Barack Obama (D-IL) http://twitter.com/BarackObama
Governor Arnold Schwarzenegger (R-CA) http://twitter.com/schwarzenegger

 

Political Parties
Liberal Democrats (UK) http://twitter.com/libdems
Massachusetts Republican Party http://twitter.com/massgop
Michigan Democratic Party http://twitter.com/michigandems
Republican National Committee http://twitter.com/RNC
Singapore Democratic Party http://twitter.com/yourSDP

 

Public Transit
BART (San Francisco) http://twitter.com/SFBART
MTA Bike Plus (NYC) http://twitter.com/mtaplusbike