Design
CircuiTree (US) Information For The Printed Circuit Board Industry
Circuits Online (NL) Online Electronics
Electronics-Lab.com (US) The electronic hobbyist corner
EverythingPCB (US) The Printed Circuit Industries Product, Service and Resource Guide
IPC Designers Council (US) An International Network of PCB Designers
MFAD (FR) Business Directory
Ohmega (US) The Company that makes Planar- Buried- Integral- or Embedded Resistors
PCB Design Directory (TH) The Biggest and The Best Directory about PCB Design on the Internet
PCB Matrix (US) PCB Design For The 21st Century & Beyond
Printed Circuit Buyer's Resource Center (US) PCB News, Information & Links
SMTinfo (NL) Links To PCB Assembly Information
SMT net (US) SMT & Surface Mount Technology Electronics Manufacturing 
Switches Reference Center (US) Micro Switch, Toggle Switch and Pressure Switch
TreasurePCB (US) Your Map To Printed Circuit Design, Fabrication, Assembly Services, Software And Materials
Magazines
Circuits Assembly Magazine (US) The Journal for Surface Mount and Electronics Assembly
EDN (US) Information, News, & Business Strategy for Electronics Design Engineers
ICONNECT007 (US) Connecting the global electronics supply chain
Printed Circuit Design & Manufacture Magazine (US) A Forum for the Electronic Interconnect Industry
SMT Magazine (US) Surface Mount Assembly of Printed Circuit Boards
Standards
ANSI American National Standards Institute
CENELEC European Committee for Electro Technical Standardization
CSA Canadian Standards Association
DIN Deutsches Institut für Normung e.v.
ECA Electronic Components, Assemblies, and Materials Association
EIA Electronic Industries Alliance
EIPC European Institute of Printed Circuits
ENEC European Norms Electrical Certification
EREA Association of European Research Establishments in Aeronautics
IEC International Electro Technical Commission
IEEE The Institute of Electrical and Electronics Engineers
IPC Institute for Interconnecting and Packaging Electronic Circuits
ISO International Organization for Standardization
JEDEC Joint Electron Device Engineering Council
NEMA National Electrical Manufacturers Association
PCI-SIG The Peripheral Component Interconnect Special Interest Group
PICMG The Neutral Promoter of the Compact PCI technology
UL Underwriters Laboratories Inc.
VDE Verband Der Elektrotechnik Elektronik Informationstechnik e.v.
Tools
CADdepot CAD Shareware, Demos, Free Utilities and Add-Ons
Creepage / Clearance Calculator Creepage and Clearance Calculator
Saturn PCB Design Toolkit Trace Length, Differential Pair Impedance, Trace/Via Current & DC Resistance Calculator
The SMD Code Book An index of surface mount device codes, data and equivalents
UltraCAD Design Calculators A Variety of PCB Calculators