Opportunities at Cabrillo
Linux isn't hard
You really don't need to take any classes to use Linux. Linux comes with a graphical user interface much like Windows and Apple's Mac. So you can play games, browse the Web, compose documents, and create graphics without much of a learning curve. A Linux User's Group like CLUG can help you install Linux on your computer and you'll be ready to go.
CIS 90, Introduction to UNIX/Linux
If you want to know more about Linux, Cabrillo College has some great resources. CIS 90, Introduction to UNIX/Linux, will help you get comfortable using a command line interface as well as familiarize you with the general design of the Linux operating system. If you think you already know Linux, CIS 90 is also a good choice. You will probably learn more about Linux than you thought there was to know. CIS 90 is taught by Jim Griffin who is not only a UNIX/Linux expert but also genuinely embraces teaching as a vocation.
Skills Certificate
Cabrillo College offers a Skills Certificate for UNIX/Linux System Administration with courses in Installation and Configuration, System Administration, TCP/IP Administration, and Linux Network Services. There are also two UNIX-oriented programming courses at Cabrillo, UNIX/Linux Shell Programming and Perl Programming in a UNIX Environment.
Linux and you in the future
A nice thing in regards to learning about UNIX/Linux is that what you learn will not be obsolete next year or even in 10 years. I really don't want to look too far into the future but UNIX has been around since the 1970s and it has a solid following in industry. Linux is gathering energy in the PC world. I'm guessing that if you got a Skills Certificate, it'd be money in the bank :-)