Beginners Sites

Kernel Newbies
The first place to go if you aspire to work on the kernel

Beginners Guide to Linux
A comprehensive guide to doing everything the first time with Linux.

The Linux Tutorial
As the name implies a directory of tutorials, but there are also hundreds of good articles and forum topics on the site as well.

Linux Planet
More tutorials and how-to's than you can shake a penguin at.

Five Ways to Contribute to Open Source without Coding
A must read resource for those who want to help but aren't sure what they can do.