Links

Mentor
From the website, after login, is possible to download the viewer for PADS Layout files:
www.mentor.com

PentaLogix
From this website is possible to download a freeware viewer for Gerber files: Viewmate
www.pentalogix.com

CAM350
From this website is possible to download a freeware viewer for Gerber files: CAM350
www.downstreamtech.com

Saturn PCB Toolkit
From this website is possible to download a freeware toolkit that can help with the PCB development: Saturn PCB Toolkit. It includes the calculation for current vias, traces width, bandwidth, differential pair, mechanical data, impedence, unit conversion, planar inductor, thermal resistance and more!
www.saturnpcb.com