Job fairs are a great way to meet potential employers and practice your interviewing skills. Employers can give you feedback on your resume and you get to practice answering questions about your experience and your work habits. Make sure you check out the resources for cover letters, resumes and interview skills as well in the getting hired
Targeted Job Fairs, which is run by DICE.com, offer technical career fairs throughout the U.S. The 2008 schedule lists by date and location.
Information on career fairs throughout 2008. These job fairs are sponsored by Monster.com and are organized by geographical location.
CareerBuilder has their job fairs organized by date and location. They usually have 3-4 months posted at a time, so be sure to check back if you location isn't on this list yet. They also sometimes hold "online" career fairs, which are great for those that live further out from the bigger cities.
FedJobs is a job site dedicated to jobs with the Federal Government. The website has a page dedicated to upcoming career fairs.