To bring up KyleXY's concern on the regulations of these types of gambling sites, whats to say if you hosted your website out of the USA, I've come across a few gambling websites that opted into hosting there sites in Russia to try to overcome these regulations.
It is a pretty good idea not charging commission to users, and would probably in a marketing sense make your service very popular. Although there are just to many gambling sites on the web, its not really a great business to get into, and getting advertises to a new startup website is very hard. You would have to launch the site, bring in alot of traffic from some kind of marketing method, and then go directly to the advertisers themselfs. Marketing costs for gambling sites are one of the highest, so you would need alot of funding for startup.
Good luck!
'A business has to be involving, it has to be fun, and it has to exercise your creative instincts.'
- Sir Richard Branson