http://www.metap.org/13-going-pro/48-what-you-need-to-start-an-online-casino
http://www.wikihow.com/Start-an-Online-Casino
http://www.viaden.com/products/casino_faq.html
Food for thought is this quote from the first site above:
Setting up an online casino is far more involved than many think, and the level of cost can be frightening, however for well ran, successful casinos the profits are there to justify the costs, and even at a $1 million start up cost, a good casino would expect to regain that outlay inside a year.