The lack of a single discrete word to indicate the plural of "you" is one of the larger curiosities of the English language. The "proper" plural for "you" is simply "you". One is supposed to be able to tell from the context whether the "you" is singular or plural. As this rarely happens in real life, we are forced to use non-standard terms to indicate plurality. Where I live, "you all" is the standard in polite conversation while its contracted form "y'all" is common among friends. Unfortunately, both terms have a patina of yokelness about them. "You guys" has made some inroads in the past few years though many southern women view "guys" as being male specific and are offended by it. Nobody down here would be caught dead using "yous" or "youns". We give Yankee transplants thirty days to drop the habit, or else. Personally, I usually use "you folks" as it is gender neutral and doesn't make me sound like a bumpkin.

Bruce