The Las Vegas Review-Journal reports that the Nevada Gaming Control Board has alerted the state's casinos to the existence of card-counting programs for the iPhone and iPod touch. Card counting is a strategy for card games mostly commonly applied to blackjack in which a player tracks the values of cards being played to determine when the cards remaining to be dealt are more likely to be in the player's favor, and adjusts his or her betting accordingly.
Card counting is not illegal in Nevada casinos. However, using a device to aid in the counting of cards is considered a felony under Nevada laws governing cheating, control board member Randy Sayre said.
Gamblers using the iPhone card-counting program can be detained by casino operators and arrested by state gaming agents.
While the specific application described in the alert was not identified in the news article, the description of the application suggests that it may be A Blackjack Card Counter [App Store]:
The program uses four different strategies for card counting. It also operates in the "stealth mode," in which the phone's screen is shut off. The program can be run effortlessly without detection as long as the user knows where the keys are.
The Nevada gaming commission was tipped off to the existence of card-counting iPhone applications by the California Bureau of Gambling Control, and although the Nevada board has not received any reports from casinos about players using the applications, they decided to alert the state's casinos in order to raise awareness of the issue.