I agree about talking to the alcoholic when he or she is sober. Don't even bother when they are under the influence.
Try not to be angry or shame the alcoholic - that just feeds their addiction even more. You have to set very clear boundaries as to what is acceptable and what is not acceptable - and you have to do it in a firm, calm way.
This is really difficult to do when you are angry and upset, by the way!
Robin
PS - Going to Alanon is really helping me stay sane when dealing with the behaviour of the alcoholic in my life.