Documentation:
Ubuntu Documentation
http://help.ubuntu.com/
Documentation on Ubuntu, Kubuntu, Xubuntu
 
Unofficial Ubuntu Starter Guide
http://ubuntuguide.org/
 

 

 
Useful Links:

 

 
Training:
HOW-TO: Adobe Photoshop CS2 on Ubuntu - 8 steps!
http://blog.publicidadpixelada.com/2006/10/10/h...
This HOW-TO covers up the whole process of installing Adobe Photoshop CS2 on a Ubuntu box in a few simple steps.
 
Set Up Ubuntu-Server 6.10 As A Firewall/Gateway For Your Small Business Environment
http://www.howtoforge.com/ubuntu6.10_firewall_g...
 
Learning Ubuntu made easy
http://enterprise.linux.com/article.pl?sid=06/1...
Linux.com
 
How to install ANYTHING in Ubuntu!
http://cutlersoftware.com/ubuntuinstall/
A graphical guide for all new users with a Windows background using Ubuntu
 
Ubuntu Training
https://wiki.ubuntu.com/Training
Includes Ubuntu 7.10 Desktop Course, with student and teacher manuals.