Gambling 911 has published their updated list of state laws that pertain to Internet gambling. Here's summary...

Illinois - While a misdemeanor, the law currently on the books does apply to internet gambling (express internet prohibition). This is the only state that also strictly prohibits advertising within Illinois for online gambling venues (i.e. billboards, newspapers, etc.. that target residents of that state). Gambling911.com has had a strict policy in place for the past few years never to solicit Illinois state residents directly.

Indiana - There is express internet prohibition presented in Indiana's state law and - while never enforced against gamblers - the penalty is considered a felony only if the betting activity is via a syndicate or group, otherwise, placing simple wagers over the internet would be considered a misdemeanor. This state has long been a foe of online gambling since the industry really got underway in the late 90's.

Louisiana - State law prohibits placing of bets via the internet. Penalty is a felony only if betting through a syndicate or group, otherwise it is considered a misdemeanor. Recent warrants against certain principals in online gambling companies by the state of Louisiana show they are seriously enforcing this law and could potentially come after those who gamble online as well.

Montana - Oddly enough, Montana has made internet gambling expressly prohibited, punishable by a misdemeanor.

Nevada - Does not allow internet gambling across state lines.

Oregon - Expressly prohibits internet gambling by its residents.

South Dakota - Only applies to those in the actual gambling business so there is no explicit law prohibiting residents living in that state from gambling online who are not employed or otherwise acting as part of a gambling-related business.

Washington (State) - Last June, the state became the first to make betting over the internet a Class C felony regardless of whether you are betting as part of a syndicate or alone in your own living room. The law is currently about to be appealed. For now, Gambling911.com actively warns against betting over the internet if you happen to reside in Washington State.

Missouri, New York, Florida and New Jersey have in the past gone after online gambling operators or those facilitating money transactions via online gambling operators (New York's case against PayPal and Florida's attempts to stop Western Union transactions during the late 90's). None of the states have adapted laws that would penalize actual gamblers from betting online however.