I wish I had arms like her too! There are many different exercise programs out there that work your arms and shoulders. The main things to keep in mind are that you need to have relatively low body fat so that your muscle definition comes through, and you need to work your muscles out regularly for a period of at least 3 to 4 months before you will see results.
Many professionals will use low carbohydrate high protein diets to get the body fat % that they need, as the high protein will also aid in muscle recovery and help build the muscle. The mainstream thought is that you shouldn't work out the same muscles each day, so instead many people will leave at least a day to two day's rest between a workout that involves the same muscle group. For example:
Day 1: Work out arms (e.g. dips, bicep curls, shoulder press)
Day 2: Work out legs (e.g. squats, lunges)
Day 3: Cardio or rest
Day 4: Work out arms
Day 5: Work out legs
Day 6: Cardio or rest
Day 7: rest
Don't give up if you don't see results straight away. Persistence really does pay off in the end!