Check out mysqldumper - I think it has a schedule feature built into it. And there is supposed to be a setting to have it email you the database. That is not going to work with big databases though.
The cool thing about mysqldumper - you can back up all of your sites from one location. Lets say you have 5 sites on one server. With just one install of mysqldumper, you can backup all of your databases in one spot.