Here is another quick and easy pattern that is great for using up stash yarn. The pattern is the same for all sizes, you simply change your gauge to make sizes preemie, newborn, and baby. You can also knit these hats to go along with my other pattern Simple Seamless Baby Booties .

Gauge:
preemie: 4 sts = 1″
newborn: 3 1/2 sts = 1″
baby: 3 sts = 1″