COLUMBIA — The 800,000 South Carolinians who are eligible to vote but haven't registered have until Oct. 4 to sign up and participate in one of the country's most anticipated elections.

The State Election Commission is holding a voter registration drive today at the Statehouse, said Marci Andino, the commission's executive director.

"We're trying to do everything we can to avoid confusion on Nov. 4," she said.

GOP Sen. John McCain and Democratic Sen. Barack Obama are expected to draw high turnout and a record number of new voters to the polls on Election Day.

Andino said twice the number of voters, 122,000, registered during the first six months of 2008 compared with the same period in 2004. That's triple the number in 2000, she said.

Out-of-county address changes must be made by Oct. 4.

In-county changes can be made through Election Day, although Andino said voters are encouraged to make updates as soon as possible.

Andino noted that voters also can use absentee ballots. The commission's Web site details a dozen reasons that voters can request an absentee ballot, including travel, a work schedule and religious reasons. Voters can request an absentee ballot through their county voter registration office.

South Carolina Democratic Party Chairwoman Carol Fowler said Democrats turned out in record numbers, 532,151, for the party's presidential primary in January, compared to 184,288 in 2004.

"We have already registered so many new voters this year but we do know there are lots of Democrats out there who are not registered," Fowler said.

"I can't imagine how bad people will feel if they wake up the morning after the election and Democratic candidates have lost by only a few votes and they have not registered."

Rob Godfrey, communications director of the state GOP, said despite the record number of Democrats who voted in the presidential primary, Republicans outnumbered them about 2-1 in the June primaries.

"Republicans, especially with the ticket we have, McCain and Palin, are fired up over renewing the Republican lease on the White House," Godfrey said.