Here is the link (pdf format), and a good summary quote of what the article talks about. I think this is an area that will become increasing more difficult to control in the future. Technological change is inevitable, and organized and un-organized crime have the resources, and in many cases the intelligence, to use it to their advantage.

“This article examines the monetary control scheme being considered by Congress, and the possible consequences of using it as a method of enforcing a prohibition on Internet gambling. To this end, the article identifies related issues involved in Internet gambling, money laundering, and the emergent technology of electronic money. This article will seek to show that the current proposal pending in Congress to ban the use of credit cards and other payment systems as a means of preventing Internet gambling will not only fail to achieve its intended result, but may in fact unleash market forces that could have vast and unintended consequences–including the promotion of both Internet gambling and money laundering.”