From the Book - 2nd edition.
Part 1: Getting to know Arduino. Discovering Arduino ; Finding your board and your way around it ; Blinking an LED
Part 2: Getting physical with Arduino. Tools of the trade ; A primer on electricity and circuitry ; Basic sketches: inputs, outputs, and communication ; More basic sketches: motion and sound
Part 3: Building on the basics. Learning by example ; Soldering on ; Getting clever with code ; Common sense with common sensors ; Becoming a specialist with shields and libraries
Part 4: Sussing out software. Getting to know processing ; Processing the physical world
Part 5: The part of tens. Ten places to learn more about Arduino ; Ten great shops to know.