You hear/read so many things on this topic, but I find this to be very informative. I think the main idea (as with most things that can be bad for you) is to drink in moderation if you're going to nurse. Duh, right? I've nursed three babies and never had a problem sipping a beer while nursing, or beforehand. Probably not a good idea to binge drink, though.
Re: Article on breastfeeding and alcohol