Quite a bit, actually.  In 'Computing machinery and intelligence.',
Alan Turing, one of the founders of computer science, made the claim
that by the year 2000, computers would be able to pass the Turing test
at a reasonably sophisticated level, in particular, that the average
interrogator would not be able to identify the computer correctly more
than 70 per cent of the time after a five minute conversation.  AI
hasn't quite lived upto Turing's claims, but quite a bit of progress
has been made, including:

- Deployed speech dialog systems by firms like IBM, Dragon and Lernout&Hauspie

- Financial software, which is used by banks to scan credit card
  transactions for unusual patterns that might signal fraud. One piece
  of software is estimated to save banks $500 million annually.

- Applications of expert systems/case-based reasoning: a computerized Leukemia
  diagnosis system did a better job checking for blood disorders than human
  experts.

- Machine translation for Environment Canada: software developed in the 1970s
  translated natural language weather forcasts between English and French.
  Purportedly stil in use.

- Deep Blue, the first computer to beat the human chess Grandmaster

- Physical design analysis programs,such as for buildings and highways.

- Fuzzy controllers in dishwashers, etc.

Here is a cute A-Z list made by llv@linuxmail.org (Lauren Vincent):
 AnswerBus (http://www.answerbus.com/)
 Babel Fish (http://babel.altavista.com/)
 Connexor (http://www.connexor.com/)
 Deep Blue (http://www.research.ibm.com/deepblue/)
 Emdros (http://emdros.org/)
 Flip Dog (http://flipdog.monster.com/)
 Gigablast (http://www.gigablast.com/)
 Hermit Crab (http://www.sil.org/computing/hermitcrab/)
 InDiGen (http://www.coli.uni-sb.de/cl/projects/indigen.html)
 Jack the Ripper (http://www.triumphpc.com/jack-the-ripper/)
 KartOO (http://www.kartoo.com/)
 Loebner Prize (http://www.loebner.net/Prizef/loebner-prize.html)
 Mamma (http://www.mamma.com/)
 NEGRA (http://www.coli.uni-sb.de/sfb378/2002-2004/projects.phtml?action=2&w=2&l=en)
 OpenFind (http://www.openfind.com/en.web.php)
 PolyWorld (http://homepage.mac.com/larryy/larryy/PolyWorld.html)
 Questia (http://www.questia.com/)
 RiniNet (http://sourceforge.net/projects/rininnlib/)
 SIGS (http://www.acm.org/sigs/)
 Turing Test (http://cogsci.ucsd.edu/~asaygin/tt/ttest.html)
 Useroo (http://useroo.businessresearchsources.com/)
 Vivisimo (http://www.vivisimo.com/)
 WordNet (http://www.cogsci.princeton.edu/~wn/)
 Xconq (http://sources.redhat.com/xconq/)
 YY (http://www.yy.com/)
 Zabaware (http://www.zabaware.com/)

One persistent 'problem' is that as soon as an AI technique trully
succeeds, in the minds of many it ceases to be AI, becoming something
like Engineering.  For example, when Deep Blue defeated Kasparov,
there were many who said Deep Blue wasn't AI, since after all it was
just a brute force parallel minimax search, despite minimax search
being one of the great early successes of AI.  Nowadays, people are
still studying all sorts of things that are currently considered the
prerequisites of intelligence, such as intuition and emotion, but you
can bet that if and when they solve some part, some will say "oh,
that's just Engineering..."

ref:
Alan M. Turing. Computing machinery and intelligence. Mind,
LIX(236):433-460, October 1950. (http://www.abelard.org/turpap/turpap.htm)

Sheiber, S, "Lessons from a Restricted Turing Test". Communications of
the Association for Computing Machinery, volume 37, number 6, pages
70-78, 1994

Some parts © 2009 Advameg, Inc.