The answer depends on your definition of AI.
"Weak AI" has been around for quite some time. There has been a very primitive form of it put into the computers in cars for the past 20 years or so. Weak AI is a learning algorithm system that is for a specific task, such as the operation of an engine. Outside the environment that it was programmed for, it is basically worthless. This is also the type of AI used in video games.
"Strong AI" is artificial general intelligence. To my knowledge, it has not been implemented yet. Strong AI would be able to adapt to different circumstances, be self-motivated, among other traits. (Honestly, if people would stop arguing about what traits it should have and just work on the darn thing, they might get somewhere.)
Given current technology, it can be done now. The computing power exists now to put together such a machine. The problem is the software.
I have been working on the subject for over 20 years, and only in the past year or so have I solved the psychological issues involved with an artificial general intelligence.
With the right funding, I should have a working model of a creative thinking, self motivated, problem solving artificial intelligence system in less than a year. Since I have been working on my own dime, though, it may be a little bit longer.
Okay, some of you will probably think this is a little boastful, but time will tell if I am right.