Below are some links for Arduino resources. There are a variety of items from handbooks to YouTube videos.
Arduino Programming Notebook - A beginner's guide to working with the Arduino
Arduino Microcontroller Guide - A packet from the University of Minnesota for beginning with Arduino
Beginning C for Arduino - An extensive book for programming with the Arduino
Arduino Website - Tutorials about Arduino from Arduino. It uses the built in examples
Adafruit - An introduction from Adafruit. This is the site referred to at MATI.
Paul McWhorter YouTube - A series of videos with code and examples of different Arduino uses
Arduino For Beginners YouTube - A walkthrough using Arduino from Programming Electronic Academy
Jeremy Blum YouTube - A series of videos with code and examples
SparkFun Training - An 8 hour video of a class put on by SparkFun.