Nursing and drinking
It is my strong belief that if you plan on drinking, you should pump ahead of time and store your milk for your baby. No amount of alcohol in your milk is safe. Thank being said, after a certain amount of time, and based on how much you have had to drink, the alcohol is no longer in your system and it will be safe to resume nursing. When I was nursing I still pumped and dumped a full 24 hours after I had a drink.
La Leche Leage has a very informative article about this very topic. It can be found at http://www.lalecheleague.org/faq/alcohol.html
I would always wait until after Avery was asleep for the night. That way I knew I had at least 8-10hrs to get it out of my system. Not that I drink that often anyway.