I have always been drawn to, and have the desire to learn more about the "Montessori Method" of teaching children. From one of the Montessori activity books at our local library (Teaching Montessori in The Home and Child's Play) I discovered an activity called Pouring 1 to 1. I've seen a few variations, all with an end result of the child becoming self sufficient and able to pour their own drink.
We actually started off by using rice (other suggestions are using pom poms, beans, etc.) and moved on to water when my daughter was proficient with the rice. She still enjoys, and will spend a long time pouring the rice over and over and over again.
My daughter takes great pride in being responsible for pouring everyone's drinks at mealtimes, and I love the fact that she can get her own drink when she is thirsty!