Even though I wrote this Hub: http://hubpages.com/business/Job-Search-Engine-Rev... I find that SimplyHired.com and Indeed.com scour the Internet and pick up all jobs listed. These two don't always have the same jobs and there is often some overlap between the two. I always check both of these first. They also have sites in most major countries, listed at the bottom of their homepages. These have helped me help hundreds of others to find jobs.
Also look at the WIA jobs offices websites in each state and county in which you are interested.