Check out the open issues for a list of who is hiring as well as available candidates. Listings are organized using labels. Feel free to create a new issue if you have a position to fill, are actively looking for work, or just want to passively be included as available for hire.
Once a week, the Stale bot will flag postings (issues) older than 90 days as stale. If the postition is still available, comment on the posting within 7 days and bot will ignore it. If the position has been filled or is no longer applicable you can either go ahead and close it yourself or you can leave it alone and the bot will close it automatically the following week.