Here are some articles and FAQs from the LLLI website about dealing with oversupply issues.
Finish the First Breast First
Overactive Let-Down: Consequences and Treatments
Common Side Effects of an Overactive Let-Down
Is Milk Supposed to Leak? (Note: leaking, especially in the early days, is not necessarily a sign of overproduction)
How Can I Deal with My Leaking Breasts?
Too Much of a Good Thing
I am breastfeeding my baby and have an abundant supply. I'd like to donate milk for sick babies. Can you tell me how to do this?