Artificial intelligence has long been applied to the world markets - it is no secret. More accurately, they are known as Artificial Neural Networks, or ANNs. They have the ability to adapt to market conditions, and continually optimize themselves. To put it in basic terms, you tell it what you want, and it can - in theory - learn to make it happen. This technology is behind many programs used by institutions - as someone previously stated - and is only now becoming a common sight amongst the more general trading community.
Interested in coding your own? Try
Joone to create it; and,
ANN Evolve to gain a basic understanding of how they work, and how to construct one. It can be rather complex for the beginner, especially when you get into all the different methods for "learning"; however, it is proving successful for many. There are even simplistic ANN plugins for many popular trading programs (TradeStation, MetaTrader, etc.)
Research Example:
http://citeseer.nj.nec.com/20949.html
Public Application Example:
Trading Solutions
-Justin