By Slash Lane

Published: 04:00 PM EST

Mozilla on Tuesday released Firefox 3, a major update to its popular open source Web browser that's being billed as 'two to three times faster' than its predecessor.

Available immediately as a free download, the browser comes in approximately 50 languages and culminates a three-year effort on the part of thousands of developers, security experts, and testers from around the world.

"We're really proud of Firefox 3 and it just shows what a committed, energized global community can do when they work together," said Mozilla chief executive John Lilly.

Among the browsers 15,000 improvements are a new full-page zoom function that displays a portion of a Web page up close in seconds, and a smart location bar that learns as people use it, adapting to user preferences and offering better fitting matches over time.

Mozilla is also looking to raise the bar for security with new malware and phishing protection tools that offer protection from viruses, worms, trojans and spyware. One of these tools, called Instant Web Site ID, allows users to easily verify that a web property is what it claims to be, rather than a rogue website aimed at copping their personal information.

Firefox 3 was built on top of the redesigned Gecko 1.9 layout engine, which enables the browser to render Web pages two to three times faster than Firefox 2 all while using less memory, according to Mozilla. It also sports a new Add-ons Manager with support for more than 5,000 add-ons, allowing users to manage tasks like participating in online auctions, uploading digital photos, seeing the weather forecasts, and listening to music, all from within the browser.

With the release Firefox 3, Mozilla has also kicked off "Download Day," a community-wide grassroots campaign to set a brand new Guinness World Record for the greatest number of software downloads in 24 hours.