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No, you are running a gambling site. This is legal in Nevada, and Atlantic City, NJ, as well as on certain Tribal Lands. All of these locations strictly control gaming, and very few allow internet gaming of any sort.
Opening up such a site is a good way to find yourself in trouble with state regulatory agencies, and potentially local law enforcement.
For a very good summary of gaming laws by state, see this website: http://www.gambling-law-us.com/State-Laws/