Drinking regular beer will not hydrate you, as alcohol suppresses the hormone responsible for stopping urination. However, low strength beers that are <4% alcohol can hydrate you. Provided you don't drink too many of them.
Alcoholic and caffeinated beverages, such as coffee, teas and colas, are not recommended for optimal hydration. These fluids tend to pull water from the body and promote dehydration. Fruit juice and fruit drinks may have too many carbohydrates, too little sodium and they may upset your stomach.