oSync is a free cross-platform utility for Windows, Linux and Mac OSX based computers that allows you to backup your Opera 9.x profile data which includes contacts, notes, mail, certificates, wand information to an online server as well as synchronize favorites & bookmarks across multiple computers. A complete list of files and directories that can be backed up can be found here.

oSync also contains some useful tools like the Bookmark publisher which converts favorites contained in Opera’s .adr format to an HTML file and allows you to publish it to an HTML page. You can either select a My Opera online account or your own FTP server for storage option.

Download oSync for Windows here. Versions for other OS can be found on the homepage.

Make sure you read the user guide before attempting to setup a sync relationship.