I use Apple Backup to backup my key files to a second hard drive. This works well except that when you select which files to backup you can't choose hidden or system files. As I use my Mac for web development utilising PHP and MySQL, I want to backup both my source code and my MySQL data. To add a hidden file to the backup list, try the following. In Terminal, type:
open /usr/local/mysqlThis opens the MySQL folder; now select and drag and drop the data folder onto your open Backup window. Now you can backup up your MySQL data. You can use a similar trick for other hidden folders.
Mac OS X Hints
http://hints.macworld.com/article.php?story=20031218051241640