The Library Job Search 
NETWORKING
A large part of the job search process is speaking with personal and professional contacts about your career goals. Personal contacts include family, friends, faculty, etc. Professional contacts are your co-workers, former employers, librarians and library students you meet at conferences, meetings and other professional events. The line between personal and professional is very thin. Many people you know will fall into both categories. Just be sure to talk to everyone you know about your job search and career aspirations. You never know when someone you know will have information and/or connections that can assist you with your job search.
professional associations
Part of the networking process is identifying professional associations in your field. Most professional associations maintain websites and many of these sites contain career-related information as well as job boards that post opportunities nation-wide. Oftentimes, you can access this information without a membership. However, I strongly recommend becoming a member of at least one professional organization in your field. Members receive copies of organization's publications, discounted registration rates for conferences and more. If an organization has a local chapter you can get involved by attending chapter meetings and other social events. Participating in these activities allows you to meet other library professionals and widen your network of social contacts. Note: Most organizations offer memberships to students at a discount. And if you’re currently enrolled in a MLS program, you can get involved with the student chapter of an organization.
Here is a list of some professional library associations to get you started:
American Library Association - http://www.ala.org/
Public Library Association - http://www.pla.org/ala/pla/pla.cfm
American Association of School Librarians - http://www.ala.org/ala/aasl/aaslindex.cfm
Association of College and Research Libraries - http://www.ala.org/ala/acrl/index.cfm
Special Libraries Association - http://www.sla.org/
Medical Library Association - http://www.mlanet.org/
American Association of Law Libraries - http://www.aallnet.org/
To find additional professional associations, check your local library for the following resources:
The Encyclopedia of Associations: National Organizations of the U.S.
Provides contact information, including email addresses and websites, for over 3,000 non-profit membership organizations in the U.S.
Weddle’s 2007/8 Guide to Association Websites
Lists over 1,900 professional organization websites and includes the type of career services they provide.