Fenugreek! This is a herb commonly used in curries. However, I recently discovered it can also help boost breast milk production.
One of the girls from my antenatal class mashed up some Fenugreek seeds the other day and made a drink from it ... and the next day she produced 300mls from each breast. She swears the milk was so abundant that when she was expressing from one boob, it was flowing freely from the other boob too.
I have to admit, I tried her concoction myself without much joy. But I will persevere ... watch this space.