ePanorama.net : from the old but
venerable Tomi Engdahl's Electronics Pages. A HUGE repository of electronics
related informations
Internet FAQ Archives : 99% of
world's questions are answered there... In particular in
comp.sys.embedded.
ChipCenter : Another source of
information on virtually any subject. Moreover their "AskUs" free
support service is fantastic.
VK2TIP Ian Purdie's
electronics tutorial radio design pages : A very interesting repository of
tutorials and schematics, mostly RF oriented.
AC6V's TECHNICAL REFERENCE :
Another very good "links" site, referencing zillion of electronics
and ham-radio sites.