Free Computer Science and Information Technology Books

Version Control with Subversion - by Ben Collins-Sussman, Brian W. Fitzpatrick & C. Michael Pilato
Bruce Eckel's free books page - Highly recommended, author of Thinking In Java series.
The Art of Unix Programming - by Eric S. Raymond.
Structure and Interpretation of Computer Programs - by Hal Abelson, Jerry Sussman &Julie Sussman
Free as in Freedom - Richard Stallman's Crusade for Free Software - by Sam Williams
PHP 5 Power Programming - by Andi Gutmans, Stig Sæther Bakken, & Derick Rethans
PHP Cookbook - by David Sklar & Adam Trachtenberg
The Definitive Guide to symfony - by Fabien Potencier & François Zaninotto
Bash Guide for Beginners - by Machtelt Garrels
Linux Administration Made Easy - by Steve Frampton