W3.org:

W3.org has 287 URLs listed in 163 Dmoz categories.

W3C Security Resources
Links to security initiatives such as PICS Signed Labels, and XML-DSig. (W3C)
http://www.w3.org/Security/
Top/Computers/Security/Internet

W3C P3P Project Main Page
Platform for Privacy Preferences Project, P3P is a protocol for privacy protection on the Web. The W3C is the governing body issuing the standard.
http://www.w3.org/P3P/
Top/Computers/Security/Internet/Privacy/Protocols

Sites using P3P
A list of sites compliant with the P3P specifications. Compiled by the W3C and a useful reference for learning by example.
http://www.w3.org/P3P/compliant_sites
Top/Computers/Security/Internet/Privacy/Protocols

World Wide Web Consortium (W3C) P3P Validator
This P3P Validator is compatible with P3P spec from Sep 15, 2000 to Sep 28, 2001. Test you implementation's compliancy and be alerted to errors.
http://www.w3.org/P3P/validator/20010928/
Top/Computers/Security/Internet/Privacy/Protocols

The Platform for Privacy Preferences 1.0 Deployment Guide
This is a guide for site operators deploying the Platform for Privacy Preferences (P3P). It provides information on the tasks required, and gives guidance on how to best complete them.
http://www.w3.org/TR/2002/NOTE-p3pdeployment-20020211
Top/Computers/Security/Internet/Privacy/Protocols

APPEL1.0 Working Draft
APPEL: A P3P Preference Exchange Language 1.0(APPEL1.0). A language for describing collections of preferences regarding P3P policies between P3P agents
http://www.w3.org/TR/P3P-preferences/
Top/Computers/Security/Internet/Privacy/Protocols

The Platform for Privacy Preferences 1.0 (P3P1.0) Specification
This is the specification, W3C recommendation date: 16-05-2002, of the Platform for Privacy Preferences (P3P). This document, along with its normative references, includes all the specification necessary for the implementation of interoperable P3P applic
http://www.w3.org/TR/P3P/
Top/Computers/Security/Internet/Privacy/Protocols