Obama has 6-point lead on McCain

WASHINGTON (Reuters) - Democrat Barack Obama has opened a 6-point lead over Republican John McCain one day before the White House rivals meet in their final debate, according to a Reuters/C-SPAN/Zogby poll released on Tuesday.

Obama leads McCain 49 percent to 43 percent among likely U.S. voters in the latest four-day tracking poll, up slightly from Obama's 4-point advantage on Monday. The poll has a margin of error of 2.9 percentage points.

(Reporting by John Whitesides; Editing by Philip Barbara)