A nice video introduction to the capacitor, which we will be using extensively while learning about arduino and building environmental sensors. 

Here is a nice video introduction on resistors from Make.

The website Fritzing.org is a good resource for learning Arduino. Specifically, it has a program that you can download to sketch out the circuit that you will be using for the Arduino program. Secondly, they have a service that allows you to create a printed circuitboard, which will be useful in the future.