BackupBuddy WordPress Plugin:
Backup your entire WordPress installation in minutes with this WordPress Plugin. Widgets, themes, plugins, files, and SQL database, the entire package!
Just like your laptop or desktop computer, you should be doing regular backups of your website. With BackupBuddy you can schedule backups and have them sent off-site to Dropbox, Amazon S3, Rackspace Cloud, or your email. Or download them right to your desktop.