Here are the links, arranged by category.
Feel free to suggest more by sending an e-mail to
thinkplan
art & ideas
Grist
environmental news & commentary
Conscious Choice
Adbusters/Culture Jammers
get mad about corporate disinformation
Inhabitat
News and information about sustainable tech
Pood's site
photography, cycling, music
books
The No Asshole Rule
this link takes you to author Bob Sutton's blog
Man Without a Country
Wiki entry discussing Kurt Vonnegut's final book
Timequake
Wiki entry discussing Kurt Vonnegut's 1997 book
practical
Instructables
Useful and funny Do-It-Yourself site with videos
Cycling Forums
news
Guerrilla News Network
Democracy Now!
peak oil
Energy Bulletin
Post Carbon Institute
James Howard Kunstler
action — websites of people who are actually making changes
Monkeyfister
alternatives
alternative technologies, alternative ways of living, alternative ways of thinking
Sustainability Network
Square Foot Gardening
Permaculture
Cob Builder's Handbook
How to build with Cob
Cob/Strawbale
Rocket Stove