Professional Organizations
IPC –  http://www.ipc.org/Default.aspx
IPC Designers Council – San Diego Chapter - http://dcchapters.ipc.org/SanDiego/
Surface Mount Technology Association – www.smta.org
Underwriters Laboratory – www.ul.org
IEEE – www.ieee.org
National Association of Self Employed – www.nase.org

Professional Resources
RF Café – www.rfcafe.com
PCB Libraries – www.pcblibraries.com

Professional Networking
Linked In – www.linkedin.com
Plaxo – www.plaxo.com

Electronic Component  Distributors
Digikey Electronics – www.digikey.com
Mouser Electronics – www.mouser.com
Newark Electronics – www.newark.com
Arrow Electronics – www.arrowelectronics.com

EDA Software Vendors
PADS Software – www.pads.com
Mentor Graphics Corporation – www.mentor.com
Altium Inc. – www.altium.com
Polar Instruments – www.polarinstuments.com

File Transfer Services
You Send it - www.yousendit.com