These sites, while not specifically focused on libraries, will allow you to limit your results to library-specific jobs and are another great resource to look into when searching for jobs.
This list provides links to sites that provide library-related job listings. There are sites for many academic and school library jobs, as well as government jobs. Be aware that oftentimes public library jobs are posted on city websites.
Be sure to sign up for the SLIS LISTSERV; job opportunities are regularly sent out this way.
Please let me know if you have any suggestions of links to add.
Following is a list of resources that provide excellent tips for individuals searching for a library job. A few important tips to think about when applying are: