
All online brokers within the United States are regulated by the Commodity Futures Trading Commission (CFTC) and National Futures Association (NFA). Other governments, of course, have their own regulating agencies.
If you're contemplating working with a broker from another country, consult their rules and make certain they're on the up-and-up; there are people within the Forex market right now who are somewhat akin to the snake-oil salesmen traveling the frontier during the previous century, and it's very much a case of "let the buyer beware."
Computer security has come a long way in recent years, and any reputable broker offers the highest possible, so that shouldn't be a deciding factor.
