Hi,

Bumped into this [1] via Ruby-lang.org. Lots of nice online books ( called $Topic Essentials ) - short and very fast introduction to various topics - from Xen to Fedora to PHP. Esp helpful if you want a quick intro to a certain topic. Have fun.

[1]http://www.techotopia.com/index.php/Main_Page

Cheers!

Pradeepto