Yep, they did it: A team of Russian scientists has drilled 3769.3 meters through the Antarctic ice to reach the surface of buried Lake Vostok, the team announced this morning on the Arctic and Antarctic Research Institute's Web site (in Russian).
Valery Lukin, leader of the Russian team, confirmed in a press release that the team reached the East Antarctica lake on Sunday evening Moscow time. On Saturday, the drill had encountered water at about 3766 meters depth, but the team determined that it was a water lens sitting above the surface of the lake rather than the lake itself. The team collected water samples from the lens, and then kept drilling until reaching the lake surface itself. As expected, the pressurized water of the lake rose about 30 to 40 meters through the borehole and froze, plugging the borehole; the team will return next fall to retrieve the plug and examine it for signs of life.