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 forecasts between English and French. Purportedly stil in use.

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: