Tutor2u
Tutor2u: Shifts in Market Demand
This is an easy to understand site that presents the law of demand, changes in quantity demanded, and the factors that cause a demand curve to shift. It also discusses how inferior goods and normal goods respond to changes in demand.
Robert Schenk, PhD
The Demand Curve
This site discusses demand and the law of demand, and shows how a demand schedule can be transferred onto a demand curve. It also explains how a change in the price of a substitute can cause your original demand curve to shift.