Essential Software (mostly free)

Arduino: Programming environment and USB drivers

Fritzing: visual layout program for Arduino projects

Eagle: Circuit board layout software; available free in “lite” version (and for Mac!)

Documents

Make: Electronics Free introductory section of ebook from Make magazine. Good fundamentals.

Resource Sites

Resistor Calculator: Allows you to look up resistors by both their stripe labels and their ohm values

Fritzing parts library additions from Google Code project

MAKE: Blog’s Arduino Roundup: projects, tutorials, resources for working with the arduino

Tutorials

555 Timer Tutorial: Pin labels, pulse circuit, component values chart

Lady Ada Arduino Tutorial: A thorough introduction to the system and process