Google has now opened up its Jobs Search so that developers and site owners to add their content.
All that's required is the appropriate mark up, including <lastmod>, and the submission of a sitemap with the accurate <lastmod> date.
Here's details of the the job posting structured markup
[developers.google.com] and guidelines.
Google says that people already posting at LinkedIn, Monster, DirectEmployers, CareerBuilder, Glassdoor, and Facebook may also appear, too.
For bigger sites, with more than 100,000 postings, or 10,000 changes per day you'll need to "express interest" through this application. [docs.google.com