Mozilla has made the Firefox 3 Beta 3 available for download, but has warned that it is intended for " testing purposes only" and is aimed at developers rather than "casual users".

New features include improved security in the form of better presentation of website identity, malware protection, stricter SSL error pages and antivirus integration in the download manager.

Ease of use enhancements include improved download manager search and progress indication in the status bar, "resumable" downloading, full page zoom and better integration with Windows Vista, Mac OS X and Linux.

Mozilla is also aiming for "richer personalisation" by offering one-click book-marking, smart bookmark folders and better customisation of download actions for file types.

Mozilla also announced live support via instant messaging. The full release of Firefox 3 is due later this year.