Download the final official version of Firefox 3 first.

Although Firefox 3 was not officially released and made available for download until 1:00 AM on June 18th (Hong Kong Time), a few minutes ago, the installation files were uploaded to Mozilla's FTP server. Visitors who go to the FTP directory can choose to enter the Linux, Mac, or Win32 folder, then select their preferred language version for download, becoming one of the first users of Firefox 3 Final.