gigorok

This plugin allow to backup files and database and sends them to your email. 
You can setup a periodically backup.

Backup2Email

This plugin allow to backup files and database and sends them to your email

Xosen

When a post is published or updated, this plugin will send a backup email to the administrator of the WordPress 
blog with an attachment file that contains the post in XML format. The XML follows the format used when WordPress 
exports blog contents so that it can be easily used to restore the post.
The general idea of this plugin is to never loose any of your posts. If you have scheduled a backup of your 
blog once a week, its possible that you will loose the new posts published during that last week. With this 
plugin you will have a backup of all your new published posts in your email account.

New Post Automatic XML Backup by Email

When a post is published, a backup email is send to the admin with the post content in XML format.

Backup2Email vs New Post Automatic XML Backup by Email