There are a few job boards specifically for Linux, including Mojolin, BestLinuxJobs.com, HotLinuxJobs.com, and LinuxWebJobs. OpenSourceJobs.org is another place to try.
If you know embedded Linux, turn to the listings on LinuxDevices.com.
Don't overlook your local LUG. Not all have job postings online, but they're an excellent place to start networking.
If your job search fails to bear fruit, don't despair. Keep your day job, but get involved with one of the thousands of projects on SourceForge. No, you won't get paid, but you'll gain valuable experience, make good contacts, and contribute something back to the open source community.
Have we missed your favorite Linux employment resource? Post it in a comment below.