Job Search Agents
PJ Scout is one of many job search agent services that will send you job listings. The majority of them require that you register to use the service, but, all the top sites are free. Monster's Job Search Agent will send you job listings that match the profile you set up. Become a Vault.com member and you'll receive job announcements and will be able submit your resume to the database for more opportunities.
Supplement Your Job Search
Remember, email job search agents should be used as a tool to supplement your traditional job search (networking, classifieds, jobs databases, informational interviews...) and not replace it. Many people have found jobs using these services, but, it makes sense to pursue as many opportunities as possible using as many venues as you can. Job searching is partly a numbers game - the more resumes you send, the more chance you have of receiving an interview. The more interviews you have, the more chance you have of getting an offer.