This is a free pattern called "Brenda's Shrug". I've made several for myself and others, and have found it to be an easy to read and easy to execute pattern. The pattern is worked flat, with the sleeves seamed. If you have experience working sleeves in the round, you may work the sleeves that way to avoid seaming.
The resulting shrug is roomy enough to go on over a sweatshirt, sweater, etc.