Pretty simple, basic ear-flap hat. Written in US terms.
Pattern is for 0-3 months, 3-6 months, 6-12 months, 1 - 2 years, 3-5 years, 6-12 years, Teen/Adult Small, Adult Medium and Adult Large.

Updated the pattern 01/01/12. Rounds are meant to be joined with a slip stitch. I am terribly sorry if that caused any confusion. The post is fixed and cross my fingers the pattern should read proper now!