Advertisers are expected to more than double their spending on messaging and display ads for mobile devices over the next five years, a market research firm said Monday.

Spending by advertisers is projected to increase to $2.9 billion in 2011 from $1.4 billion this year, JupiterResearch said.

Currently, 22 percent of online advertisers are engaged in mobile marketing, the research firm said. Early adopters include wireless carriers and media companies, and organizations within automotive, financial services, consumer packaged goods and food services.

Brands leveraging mobile marketing tend to be youth oriented, but not exclusively so, JupiterResearch said.

Meanwhile, about a quarter of current mobile phone subscribers said they would be willing to watch advertising on their handsets if they received free phone applications in return, a survey by Harris Interactive found. In addition, 7 percent of phone subscribers said they would be interested in receiving promotional text messages, if they were relevant.

"This 7 percent coalition of the willing represents a huge market given the fact that there over 200 million cell phones in the United States," Joe Porus, vice president and chief architect for Harris Interactive, said in a statement.

Nevertheless, Porus warned carriers that they need to balance advertising revenue with the potential of irritating subscribers to the point where they jump to a competitor.

Harris based its findings on a nationwide online survey of 1,125 U.S. adults in August.