Even with Halloween still days away, many online retailers are already getting into the yuletide holiday spirit.

A recent survey of nearly 100 online retailers  -- and several thousand shoppers -- found that an overwhelming number of sites are starting their holiday promotions earlier than ever this year, according to BizRate Research, a research division of Internet shopping search giant Shopzilla.

The survey was also sponsored by Shop.org, the online shopping division of the National Retail Federation, an industry trade group based in Washington.

Among retailers polled, 38.5 percent said they had already launched their holiday marketing efforts, while more than half said they would start by Nov. 4, the survey found.

A corresponding number of shoppers, about 35 percent of nearly 3,000 polled, said they planned to start their holiday shopping by Halloween, the survey found.

"Due to shipping deadlines, online retailers have a shorter promotional window for the holiday season, so many of them want to be first out of the gate to debut holiday merchandise," Scott Silverman, the executive director of Shop.org, said in a statement. "Multi-channel retailers are very good at responding to what their customers want and, this year, customers want to start shopping early," Silverman said.

Among other online promotions, more shopping sites this year will be offering free or discounted shipping, which shoppers identified as one of the biggest draws in deciding where to buy online.

More online retailers said they were also investing in search-engine marketing and comparison shopping engines, while a smaller number were using blogs and RSS feeds, the survey found. About half were promoting their holiday sales in traditional media, including magazines, newspapers, radio and television, the survey found.

Online retail sales in the fourth quarter are expected to increase by 23 percent over last year, hitting $33 billion compared to $27 billion in 2005, according to estimates by Retail Forward, a marketing research firm based in Columbus, Ohio.

By contrast, sales at brick-and-mortar stores are expected to grow by just 5.5 percent this year, below the 10-year average growth in holiday sales, the firm said.

"E-commerce will continue to represent the fastest-growing retail sector this holiday season, propelled by retailers becoming more aggressive online and consumers growing more comfortable with virtual shopping," said Frank Badillo, the firm's senior economist.

Despite that growth, online retailing only accounts for about 3 percent of all retail sales, the firm said.

Still, FedEx (NYSE:FDX)   is anticipating the rise in online sales this season to help boost its ground-delivery services to a record-high 8.9 million packages in a single day -- on or about Dec. 19, the company said.

"Online retailing continues to show strength as more and more consumers make online shopping a part of their holiday tradition," Gene Huang, FedEx chief economist, said in a statement on Tuesday.