GNUnet is a framework for secure and anonymous peer-to-peer networking that does not use any centralized or otherwise trusted services. Currently, the framework offers censorship-resistant file-sharing, messaging, VPN, GNS (a decentralized version of DNS), and much more. GNUnet is currently developed by a worldwide group of independent free software developers. GNUnet is a GNU package (http://www.gnu.org/).
JAP / JonDonym is an anonymizing proxy service. It runs as local service connecting encryptedly to centrally shared proxy cascades. This hides the individual IP addresses of its users. With JondoFox there is even a simpler to configure Firefox plugin.