I have a friend who recently informed me of their venture into the world of Linux.  I started to build up a good set of links and thought I would share.  Here you go.
 
The Ubuntu Guide - A Wiki for common setup and configuration tasks in Ubuntu.
 
Ubuntu Tweak - Simplifies some Ubuntu configuration tasks as well as application and driver installation.
 
Appnr - Find Linux Applications
 
Dual Boot Reference - For those who want to hang to Windows just in case.
 
Gnome Do - This is one of my favorite applications in Ubuntu.  Thanks to Gnome Do, I never have to swim through menus to launch an application.  Learn it.  It will save you time.
 
Here are some good Linux blogs.
 
Productive Linux - A blog about performance and efficiency in Ubuntu.
 
OMG! UBUNTU! - A blog that follows Ubuntu news very closely.
 
Full Circle Magazine - A Ubuntu magazine.
 
Mark Shuttleworth's Blog - Founder of Canonical Ltd. which backs Ubuntu.