This hair-style is called a faux-bob, and it's very easy to achieve.
1. Wash your hair, then curl it all over using a 2" curling iron. Take quite large pieces of hair (1-2 inches) to create quite soft but large curls.
2. Gather your hair as if you are going to put it in a ponytail, then pin the bottom of your 'ponytail' to your scalp using hair pins. Spread out to make sure your hair is 'bobbed' at the front too.
And you're done!
It's quite difficult to explain this kind of hair style in a written tutorial, so if you're still not sure, search for 'faux curly bob' on youtube. This link is a great example!
