Whenever I have a problem that a Google search cannot solve, my first stop is the Ubuntu Forums. The user base is friendly, mostly, and very helpful with any number of problems you throw at them. I have found solutions to many issues via these forums.
Ubuntu Tutorials is a useful site that offers…tutorials on various aspects of Ubuntu.
I am not a big fan of this site in general, but the Linux portion of Digg offers useful links from time to time if you can stomach the endless TOP 20 REASONS LINUX IS BETTER THAN WINDOWS $$#$@$##$^^&^&*#$@#@ style posts.
Lifehacker also has a surprising amount of Ubuntu and more general Linux news, links, and tips as well.