The laws will depend on why the web cam is being set up. Is it for security only? As in taping underage people trying to get service. Is it because you want to set up a web site depicting how crazy people can act with a few drinks? If it is the web site you could be headed for trouble. In these cases you need you have the people who will appear on the web cam sign a declaration relaeasing their permission for you to be taping them.
In canada the use of a web cam is illegal unless you are using it with the prior written permission of each of the people who are caught on camera. If it is too use to expose a illegal practice that you know is going on in a bar? Sorry tapes, video, etc can not be used in a court of law as evidenvce not even telephone tapes. Maybe if you were to explain why you want to use it, then I could help you better