At the AMS site:
Grigoriy Perelman of St. Petersburg, Russia has declined the US$1,000,000 Millennium Prize. In March the Clay Mathematics Institute (CMI) had announced that Perelman was the recipient of the prize for his resolution of the Poincaré conjecture, one of the seven Millennium Prize Problems. Perelman's refusal was not entirely unexpected: In 2006, he declined the Fields Medal. The following statement appears on the Clay Mathematics Institute web site: On June 8-9 CMI held a conference in Paris to celebrate the resolution of the Poincaré conjecture by Grigoriy Perelman. Dr. Perelman has subsequently informed us that he has decided not to accept the one million dollar prize. In the fall of 2010, CMI will make an announcement of how the prize money will be used to benefit mathematics.