From the AP:
Ralph Nader said Sunday he will run for president as a third-party candidate, criticizing the top White House contenders as too close to big business and pledging to repeat a bid that will "shift the power from the few to the many."
Republican presidential candidate Mike Huckabee, speaking shortly before Nader's announcement, said Nader's past runs have shown that he usually pulls votes from the Democratic nominee. "So naturally, Republicans would welcome his entry into the race," the former Arkansas governor said on CNN.
Nader also ran as a third-party candidate in the 2000 and 2004 presidential elections. Though he won 2.7 percent of the national vote as the Green Party candidate in 2000, his percentage dropped to just 0.3 percent as an independent in 2004, when he appeared on the ballot in only 34 states.
Here's one reaction to a Nader candidacy from YouTube: