One of the oldest and best defenders of online privacy has to be the Electronic Frontier Foundation. This non-profit organization was founded in 1990 and they have been fighting the good fight for the past 17 years. Its funded solely by donations from regular folks. The big telcoms are not their friends so they aren’t racking in the big bucks in corporate donations.
The EFF usually ends up on the front lines fighting privacy battles in court rooms and in congressional hearing. One example of a recent court case involves a class-action lawsuit brought by AT&T customers accusing AT&T of violating their rights by illegally assisting the National Security Agency. The EFF is representing the plaintiffs in the case, Hepting v. AT&T.
One way that you can help the EFF is by buying some of their swag off their website. It makes for some interesting conversation starters at any internet/computer based trade shows. To find out more about the EFF and to buy the swag check out their website at www.eff.org.