Command Line Warriors
I saw a plug for the Command Line Warriors blog in a British Linux magazine.
An enjoyable read, to be sure, with lots of GUI content, Mac OS X stuff, general Britannia and even shell account info.
Especially notable are the iPod and Linux series, Installing Gentoo series and Intro to the OS X command line.
My quick hint for OS X users:
Go to Applications, then to the System Utilities folder, then run Terminal. That's the OS X command line (your box is running BSD Unix, and it's there in all its glory).
at the prompt type this:
top
You will see most of the running processes on your machine and the percentage of memory and CPU power they are using.
To turn off top, on the PC it's ctrl-C. Maybe it's the same in OS X. If not, try Apple-C, or just close the Terminal window.