Linkedin.com is a networking site for professionals to keep in touch with other professionals. Through these connections, it is possible to find contacts in companies for whom you would like to be employed. Linkedin also offers company and industry groups and job listings that are only found on Linkedin. It is well worth the time for any professional to become familiar with Linkedin.
"Find a Job on Linked in, Facebook, Twitter, Myspace and other Social Networks" by Brad and Debra Schepp
Careerservices.linkedin.com - Although this site is geared for students there are helpful resources here.