Mozilla Corp., which will release the first beta of its Firefox 2.0 browser Tuesday, posted Windows, Mac, and Linux release candidates on its FTP servers over the weekend.

Firefox 2.0 Beta 1 Release Candidate 1 (RC1) can be downloaded from Mozilla's FTP site, although the official Beta 1 won't be released until July 11, according to notes published by the open-source developer.

Beta 1 features improvements that include close buttons on all tabs, a search plug-in manager to more easily add and remove engines from the search box, and a browser restore feature that recovers the browser and all tabs if the application crashes or freezes. Other enhancements range from an integrated spell-checker to an anti-phishing tool that warns users when they surf to a site blacklisted by Mozilla.

As the browser went through three alpha test stages -- the last launched in late May -- developers dropped a once-touted feature, dubbed "Places," a redesigned bookmarks tool which would have let users search both browsing history and bookmarked sites simultaneously.

As is typical with Mozilla previews, downloading and installing RC1 will disable most extensions and themes. A "portable" version of Beta 1 RC1, available from a third-party site, runs without affecting existing Firefox settings, however.

In other news, Mozilla is also prepping a security update to the current Firefox, which will be labeled "1.5.0.5." The update is scheduled to ship in approximately two weeks.