I already talked about backing up your Drupal installation in my posts about updating Drupal.
Backing up the code is pretty easy – just copy your whole Drupal installation – and done.
But how do you backup the database nice and easy?
The easiest way I found was the Module Backup and Migrate.
You can easily back up the database just with a click or setup automatic backups for your systems (either saved on a server or send by mail).
You can also setup the backup to be compressed (which is handy, when you need to restore and the Server will not let you do it with a big file)
And the module also restores the database.
You can also update the Database directly with these files (outside of Drupal – useful if your provider let’s you not update the whole database via Restore – I had the problem once )
Of cause there are more cool options waiting in the module (I just never used them 😉 ) and if you search for Backup on drupal.org you find some more Backup and Restore projects not part of the main project (I’ve seen some backup to Dropbox once)