Where do you go to find jobs?

Monster.com
CareerBuilder.com
Dice.com
ClearanceJobs.com
MilitaryHire.com
LinkedIn.com
Indeed.com
GlassDoor.com (better for assessing companies than finding jobs)
Even Craigslist.org, if you're looking for entry-level or it's that kind of a day
If you're interested in civil-service jobs, usajobs.gov and whatever your states' employment-assistance website is.

On any of the sites where you can maintain a profile and post a resume, do so and don't let it go more than 2 or 3 weeks without updating something (even if it's just shuffling bullet points) because recruiters and HR personnel will skim for resumes less than 30 days old as an indicator that you're actively looking. If you're submitting your resume for a job, always do a cover letter where you list off the 3 or 4 most important items on the job description and match them up with something from your resume that says you can do it --- do that also if a recruiter is the one forwarding your resume, because it helps them sell you.

The number one source of real job opportunities is referrals. Many jobs are "advertised" by companies simply to test the employment marketplace, confirm salary levels, etc. Job seekers need to network. Get out, press the flesh, and talk. Have a 30 second "elevator pitch" ready and rehearsed. Have a business card to hand out (you can get them for free on the Internet). When you run out of friends and family to annoy, meet new people, make new friends and annoy them. Networking events are usually a waste of time full of others also looking for work. Socialize in places and with people where you can make productive contacts. Good luck and good hunting...

I made nearly all of my connections on LinkedIn actually.