Help with Arduino
There are endless Arduino resources on the Internet. Here are some I think are well written and simple for beginners.
An all time favorite, by Limor Fried (AKA Lady Ada)
Connecting Arduino to other things
ITP tutorial on controlling a motor or other high current load with an Arduino
Slight variation on the above circuit, showing the added base transistor which I really think belongs there.
Another tutorial from ITP, this one showing how to attach a “flicky sensor” to an Arduino. The flicky sensor (piezo tab) generates a very small voltage, too small to be sensed directly by Arduino. It must first be amplified by a circuit like this.