With a vote of 28-4, the NFL Owners have decided to change the overtime rule in the playoffs.
The team that wins the coin flip now must score a touchdown to win the game immediately. By kicking a field goal, the coin flip winner would have to give the ball back to the opposing team who could win the game with a touchdown or kick a field goal to tie the game. Once each team has possession the overtime would go back to the original sudden death format.
There are a few intricacies to the rule as well. Tom Silverstein of the Milwaukee Journal Sentinel lists them on the JS Online Packer Blog which you can read by clicking the link.