Jobs

The Copy Editor
Mediabistro.com
Hireminds.com (largely for Boston)
The Editorial Freelancers Association (you must join to get the jobs list)
Publishers Weekly
Publishing Mall
Journalismjobs.com
Newslink
Flipdog
American Association of University Presses
Society of National Association Publications
Society for Scholarly Publishing
American Copy Editors Society
American Society of Association Executives

Handy Reference Material

Google Resources -- Calculator, definitions, tracking numbers and more
PubMed
The Greek Alphabet
Merriam Webster's 10th Collegiate Dictionary
Merriam Webster's Table of Proofreading Marks
The Visual Thesaurus
Chicago Manual of Style FAQ
Proceedings of the National Academy of Science (PNAS) Standard Abbreviations and Symbols
PNAS Units of Measurement
Words for Copy Editors
MEDLINEplus/Merriam-Webster Medical Dictionary
English Club Preposition List