Of course you can have dual citizenship in Poland - all this means is that when in Poland you get treated exactly like a Pole would: you can't appeal to your US/British/whatever Embassy for help if you get into trouble.
Both my parents were born in Poland, while both my brothers and i were born in the US.
I know that there is a way for us to get dual citizenship, but I don't know how. Does anyone know the procedures? Where do I get the paperwork for it? From the Embassy?
Also what types of documentation do we need to provide from our parents?
I know that this is a long process, and I think we need to file one at a time, rather then all at the same time. And since I'm the youngest (so will probably be the last one to file) I want to get things moving for my brothers.
You need originals of your parents' birth certificates, you need to get your own birth registered in Poland and a copy of your Polish birth certificate, you need to get your Polish citizenship confirmed by Warsaw and then you need to fill in the form, pay the money, submit the photos and you should get a passport. Your nearest consulate will be able to steer you through it and it takes months (around 12 in my case).