You can get this pattern anywhere on the internet as it is very easy to make even for beginners! I made adaptations to the hat as I prefer certain stitches over the other. One book that is good to get and I have used often is "Hats & Diaper Covers" by Leisure Arts.
By the way, to all the mothers that I have crocheted hats, diaper covers, and blankets for - I am still waiting on photos!! :-) Happy Crocheting!