This is a tool that was written for use in the MythDora mythtv menu. However, In it's basic functionality it can be run via cron to do scheduled DB backups to a designated directory. MythDora by default will run this nightly and keep 3 revisions of the database in tar.gz format. It also has a rudimentary ability to burn to cd (using cdrecord) and also restore a database.

Enjoy.