About.com VPN directory
   A smattering of VPN resources including a glossary and a self-test.
   http://compnetworking.about.com/cs/vpn/index.htm

Corecom VPN FAQ Page
   Geared towards those new to VPN.
   http://www.corecom.com/external/vpn/vpnfaq.htm

Find VPN
   Directory of VPN providers, articles, and links.
   http://www.findvpn.com

How Stuff Works: How Virtual Private Networks Work
   Gives definition of VPN and an overview of general VPN topics, includes diagrams and an animation.
   http://www.howstuffworks.com/vpn.htm

NW Fusion: Research: VPNs
   This is a comprehensive collection of VPN resources and articles.
   http://www.nwfusion.com/topics/vpns.html

Tom Dunigan's Virtual Private Networks page
   This page describes IP-based VPN technology over the Internet
   http://www.csm.ornl.gov/~dunigan/vpn.html

VPN labs - research community
   VPN labs is an open community for researching, reviewing, and discussing Virtual Private Networks.
   http://www.vpnlabs.org/

Virtual Private Network Consortium
   VPNC is the international trade association for manufacturers in the VPN market.
   http://www.vpnc.org/