Musicians I know, bands I like, musicians and bands I know and like:
46bliss
Roger Kuhn
Andy Macdonald
Righteous Babe Records
Freedom Haters
Riannan Zoucha
Mahogany
Lavender Light Gospel Choir
Patti Smith
Steve Baughman

A few good places in no particular order:
Peter M Goodrich Memorial Foundation
The Lower East Side Girl's Club
Greenpeace
Amnesty International
Lesbian Herstory Archives
People for the Ethical Treatment of Animals
Heifer International
The Elephant Sanctuary
Slate
The Gully
MoveOn.org

Also available for daily clicks:
The Hunger Site
The Breast Cancer Site
The Child Health Site
The Rainforest Site
The Animal Rescue Site