You can bet on it: Sports gambling is about to expand, big time, in the United States.

Right now, the only place you can legally bet on sports is Nevada.

But on Monday, the Supreme Court struck down a federal law that prohibited legalized sports gambling anywhere but Nevada.

So what does this court decision mean, exactly?

Now that there is no longer a federal law against sports gambling, each state is free to pass laws that govern where people will be able to bet on sports and how.

"It'll be a state-by-state matter," said Eugene Christiansen, an expert on casino gambling and consultant to the industry. "I'm sure there will be a wide variety as to how fast or how slow the licensing proceeds."

Are any other states close to approving sports betting?

Six states, including New Jersey which that brought the lawsuit to the Supreme Court, have already passed laws to allow casinos to take sports bets once the federal law was struck down, according to Geoff Freeman, CEO of the American Gaming Association. Those states are New Jersey, New York, West Virginia, Mississippi, Pennsylvania and Connecticut.

Another 12 states have introduced legal sports gambling legislation.

Even in states that have approved sports gambling, it'll take some time to complete the approval process, which will require companies to be licensed in order to take sports bets.

"In the case of New Jersey I think we're talking weeks before we have sports betting in place," he said. "For most of the other states, I'd expect it start at the beginning of the football season this fall."

Related: Supreme Court lets states legalize sports gambling

How widespread will sports betting become?

There are a total of 40 states that have some kind of casino -- either state-regulated or tribal. Experts say they believe most if not all of those states will eventually allow sports gambling, simply because they won't want their own casinos to be at a competitive disadvantage with casinos just across state lines.

"It's the same reason we've seen the spread of casinos to so many states -- the states have been watching consumers going out of state to place bets," said Josh Schiller, an attorney who has represented various gaming interests. "People enjoy betting on sports."

But experts say it could still take a few years before sports books are legal in states that haven't begun the process.

"Gaming law is something that typically takes time," said Freeman. "It's more complex than many people think."

Will I be able to place a sports bet online in another state where it is legal?

Monday's decision only allows states to control gambling within their own borders. It does not open the door for interstate online gambling, or placing online bets with foreign sports books. That would require additional legislation or lawsuits.

How important is sports gambling for casinos?

Actually, it's not a very profitable business. For instance, gamblers in Nevada lost about $250 million betting legal on sports last year. But that equals only about 2% of the Nevada gaming industry's take overall.

Additionally, casinos have the potential to lose big on sports bets, unlike in house games. So sports betting can be the least profitable part of the casino, or even a money loser, according to experts.

Casinos fought for the approval to take sports bets because it's an important way to draw customers into the casinos. Otherwise, they would lose that business to illegal competitors, such as bookies and offshore gambling sites.