This is a very easy project for scraps of yarn.  The sweater is made just like the adult sweater, but sized just for kids 18 months, 2, 4, and 6 years.  This is a great beginning knitter project.  You'll need size 10 and 8 straight knitting needles, stitch holders, and approximately 300-600 yards of yarn worsted to light bulky weights depending on size.