Beer on a regular basis is bad man.... once and a while will still be detrimental but drinking weekly will certianly affect what you are going for...
Beer has lots of worthless cals and carbs... it will make cutting harder, it dehydrates you, and after a good night of beers you will be less likely to workout the next day.. There are tons of other topics on this.
Marc has this posted on his site, very very informative... the thing that scares me most is the man-boob thing
http://www.justaskmarc.com/Fitness_and_Bodybuilding_Nutrition/General_Nutrition/5_Reasons_Why_Alcohol_Will_Destroy_Your_Muscle_Gains/ Good luck in your decision.