Here's an e-mail group that specializes in job listings for editors. I'm just going to quote the group's website (here) since they explain it themselves very nicely:
"This is the American Copy Editors Society site for job postings of interest to copy editors or others in journalism and other editing careers. ACES members and others are welcome; all relevant job postings are encouraged. Please, real jobs only; no promoting of companies without actual job openings and no comments, funny or otherwise, on postings by others."
Absolutely SPAM free, this is a great resource if you're keeping your ear to the ground for [extra] work.