Not to be outdone by Microsoft's release of Internet Explorer 7 this week, Mozilla is planning the second major release of its rival Firefox browser next week.

Mozilla Vice President of Products Christopher Beard said Firefox 2.0, which should be available on Tuesday if all goes according to schedule, includes key new usability features missing in IE 7.

Mozilla also enhanced the popular tabbed browsing feature in 2.0 that Firefox introduced when it emerged two years ago as the first significant rival to IE in years, he said. Tabs allow users to navigate more easily between multiple Web pages when browsing the Internet, and Microsoft added tabs to IE 7 after Firefox's success with the feature.

In Firefox 2.0, Mozilla added a "close" button on its tabs, and also added new visual features to make the tabs appear more obvious to the user, Beard said.

New usability features in Firefox 2.0 that differentiate it from IE 7 include one that will restore the browser to pages where the user was working if a sudden OS restart is required. "If you're browser needs a restart or the OS asks you to reboot, losing all of those Web pages and content is pretty disruptive," Beard said.

Firefox 2.0 is offering two options to enable this feature for users. One way is that by default, the browser will give a user an option to restore his or her browser sessions if there is an unexpected shutdown, and the other is an advanced option to set the browser so it always restores the last five pages visited before a sudden reboot.

Like IE 7, Firefox 2.0 also has an antiphishing filter that will help protect users from divulging personal information to fraudulent Web sites. But Mozilla has taken a different approach to its antiphishing filter than Microsoft has, Beard said.

Instead of checking individual Web pages users visit against lists of known phishing sites, thus sending information from the site to third parties that keeps lists of such sites, Firefox updates its black list of known fraudulent Web sites automatically every half-hour to hour. He said this better protects users' privacy because no information from the sites they've visited is sent to any third parties.

Mozilla also has added spell-checking features to the browser similar to those found in word-processing applications. Whenever a user is typing text in the browser, such as when typing the name of a Web site, a blog entry or an e-mail, Firefox's spell checker will underline in red words that appear misspelled. Right-clicking on the word will give a user options for the correct spelling.

In addition, Firefox 2.0 has a new feature in its integrated search box that will suggest a list of search terms after a user types a few letters of a word, depending on the search engine being used. Firefox 2.0 uses Google Inc., Yahoo Inc. and Ask.com search engines as options for the search box, and each uses a different algorithm to suggest search terms, Beard said. So this feature is not disruptive to the user experience, the suggested search terms will appear in a separate pane below the search box, he added.

Though recent figures by Web analytics company OneStat.com show Firefox market share declining 1.44 percent since July -- from 12.93 percent to 11.4 percent -- Beard said Mozilla partners and users are reporting the browser is more popular than ever.

"We're not seeing a decline at all," he said. "All of our partners and friends are reporting very strong growth recently." Beard said he expects that to only continue with the introduction of Firefox 2.0 next week. Firefox currently has 70 million to 80 million users, he added.