Here is a partial list – its kind of impressive:
Reuters http://twitter.com/reuters
BBC (Off-site List) http://menti.net/?p=1
CNN http://twitter.com/cnnbrk
NY Times http://twitter.com/nytimes (The NYT also offers other sections in twitter)
NY Times Business http://twitter.com/nytimesbusiness
MSNBC http://twitter.com/dcagle
Today Show http://twitter.com/TodayShow
Wired News http://twitter.com/wired
NPR http://twitter.com/nprnews
Science Friday http://twitter.com/scifri
Planet Money http://twitter.com/planetmoney
ZDNet http://twitter.com/zdnett
Conde Nast Portfolio http://twitter.com/Portfolio
Revision3 http://twitter.com/revision3
Times OnLine http://twitter.com/TimesWorldNews
CBC News http://twitter.com/cbcnews
Orlando Sentinel http://twitter.com/orlandosentinel
Forrester http://twitter.com/forrester
Scientific American http://twitter.com/sciam
Huffington Post http://twitter.com/huffpost
CNET News http://twitter.com/CNETNews
Fox News http://twitter.com/foxnews
The Street News http://twitter.com/TheStreet_news
Google http://twitter.com/mattcutts
FarmAid http://twitter.com/FarmAid
Post Carbon Institute http://twitter.com/juliandarley
Mars Phoenix http://twitter.com/MarsPhoenix
NASA href=”http://twitter.com/NASA
LRO_NASA http://twitter.com/LRO_NASA
NORAD http://twitter.com/noradsanta
Smithsonian http://twitter.com/smithsonian
Manitoba Museum http://www.manitobamuseum.ca
Tate http://www.tate.org.uk/
Holocaust Museum http://twitter.com/HolocaustMuseum
The Franklin Museum of Science http://twitter.com/thefranklin
Obama http://twitter.com/change_gov
Starbucks http://twitter.com/StarbucksV2V
The Humane Society http://twitter.com/HumaneSociety
Red Cross http://twitter.com/RedCross
Science Friday http://twitter.com/scifri
National Wildlife Federation http://twitter.com/NWF
Farm Aid http://twitter.com/FarmAid
Tyson Foods http://twitter.com/TysonFoods
Weekend Edition http://twitter.com/WeekendEdition
Live Science http://twitter.com/LiveScience
New York Times Business http://twitter.com/nytimesbusiness
The American Public Health Association http://twitter.com/PublicHealth
Zappos http://twitter.com/zappos
Whole Foods http://twitter.com/wholefoods
H&R Block http://twitter.com/hrblock
Carnival Cruise Lines http://twitter.com/CarnivalCruise
Delta http://twitter.com/deltaairlines
Jetblue http://twitter.com/JetBlue
Southwest Airlines http://twitter.com/SouthwestAir
The Onion http://twitter.com/TheOnion
Anti Records http://twitter.com/AntiRecords
The Women’s Museum http://twitter.com/TheWomensMuseum
The Country Music Association http://twitter.com/CountryMusic
Meet Minneapolis http://twitter.com/MeetMinneapolis
American Lung Association http://twitter.com/LungAssociation
Realtor Magazine http://twitter.com/realtormag
Billy Graham Evangelistic Association http://twitter.com/BGEA
Association for International Cancer Research http://twitter.com/AICR
Ford Motors http://twitter.com/ScottMonty
GM http://twitter.com/GMblogs
Toyota http://twitter.com/toyotanewsroom
Honda http://twitter.com/Alicia_at_Honda