Google

(GOOG) - Get Report

signed a toolbar distribution deal with

RealNetworks

(RNWK) - Get Report

, further expanding its fight with

Microsoft

(MSFT) - Get Report

for the world's desktops.

Users of RealNetworks' popular RealPlayer software, which plays audio and video clips on the Internet, will also get a feature that allows people to conduct searches without going to Google's Web site. RealNetworks also will offer Firefox, which Google is pushing as an alternative to Microsoft's Internet Explorer.

"Real has been one of Google's most important distribution partners for the past two years, and we are delighted to broaden and deepen that relationship," says Google Chief Executive Eric Schmidt in a statement. "Google and Real will continue to work together in innovative ways to further improve the Web experience."

RealPlayer and Firefox also are in Google Pack, a suite of software Google offers to buyers of new computers as an alternative to Microsoft software. So far, Google's efforts outside of search haven't gained much traction despite their hype.

Google is pushing for toolbar agreements because users like them because of their ease of use. It signed a similar deal with

Dell

(DELL) - Get Report

earlier this year.

Shares of Google fell $8.56 to $366.95.