Electronic Resources Comprehensive electronics site for all your electronic resource requirements Eagle CAD layout editor -Windows and Linux systems
Kicad GPL PCB Suite
Open source PCB layout suite for Windows and Linux. Includes schematic, pcb, gerber & 3D tools Open source PCB layout software for Windows

Gerber Viewers

CamtasticDXP Camtastic Multiformat Cam Viewer -Requires registration
GC Prevue
GC Prevue - Free Gerber Viewer
ViewMate ViewMate - Gerber viewer
Gerbvt Free Gerber Viewer for Linux systems
Online Gerber Viewer Free online gerber viewer with your web browser

Printed Circuit Board Material Links isola printed circuit copper laminates
Rohm and Haas Rohm and Haas Electronic materials
Inks and coatings used on circuit boards
Final Finnish and PCB Materials