This is an awesome article on software mirroring under Linux - I came a cropper today because I didn't understand the requirement to manually configure grub before the first disk in the mirror fails (D'OH!). The article also describes rebuilding the mirrored pair when yu've added a fresh disk following a failure. Very handy indeed :)

OpenSourceCMS.com is a handy site that demos all kinds of open source CMS systems. You can go and play with them before having to go through the pain of an install yourself, and the systems are wiped clean every 2 hours so you can wreak whatever havoc you like :)

SELinux from scratch - an article from IBM on how to implement SELinux on systems that are not SELinux aware. This might be a handy way to get to understand SELinux.......