Best time to take whey protein is:
I. Right when you wake up, 20 - 40 grams. This will make you anabolic after overnight fast
II. Before workouts, 15-25 grams. This will provide amino acids during workout, so you will be less likely to burn muscle and have more energy. Could be also combined with 20-40 grams of complex carbs. Oatmeal is great for this.
III. Right after workout: 25-40 grams. Best to mix it with casein and about 40-80 grams of high GI carbs. This will promote recovery and protein synthesis =>> growth.
IV. Right before sleep. That's if you don't have casein protein or milk or cottage cheese...Otherwise skip this step
Lastly as the guy above mentioned, taking 10-20 grams between meals is also good. However, points #1, #2, and #3 are the crucial times for overall growth and muscle preservation.
With all the above being said, the more protein you take from real food sources, the less you need to supplement.