The writing was on the wall for this one what with all the 200m races at trials but the IOC made the official announcement with a few lines on their website yesterday:

More women and fewer men will paddle at the 2012 London Olympics.
All men's 500-metre races will be switched to 200 metres; a women's 200-metre K1 race will be added, and the men's 500-metre canoe doubles (C2) race will be cut. Women will compete in five canoe and kayak events and men will compete in 11.
Peter Giles says the ICF has final say on which men's race will be dropped from the Olympic program. He insisted the federation will not decide the issue until December and besides, the IOC could reverse its decision. Men will certainly lose one Olympic event, Giles said, but it may not be the C2 500-metre race.
Giles said the IOC shortened the men's races to make them more explosive and exciting for television. He said Canada supports both the drive to create exciting television and the drive to include more women in elite sport, but not necessarily the move to eliminate a canoe race and to replace a team event with an individual event.
Scott Oldershaw refused to comment directly on the changes.
"We want to focus on this competition and what is happening here," he said, "so we are pretending we don't know what has happened."