WPJobBoard is described as 'provides a robust job board solution for WordPress that easily integrates with any standard WP theme'. There are five alternatives to WPJobBoard for Self-Hosted solutions, Wordpress and SaaS. The best alternative is HivePress, which is both free and Open Source. Other great apps like WPJobBoard are Jobroll (Free), WP Job Openings (Freemium, Open Source), Jobs and Experts (Paid) and WP Job Manager (Freemium).
Jobroll - Launch a job board in minutes. Jobroll is the easiest way to create a fully customized job boards. Jobroll is a white label solution that supports custom domains, has integrated monetization options and built-in newsletter / alert system.
WP Job Manager is a lightweight job listing plugin for adding job-board like functionality to your WordPress site. Being shortcode based, it can work with any theme (given a bit of CSS styling) and is really simple to setup.