Ergoworld - Office Ergonomics (interface-analysis.com/ergoworld/office.htm): A links directory listing sites discussing office ergonomics.
Ergonomics.org links (http://ergonomics.org/links/)
U.S. Department of Defense (DoD) Ergonomics Task Force (apgea.army.mil/ergowg/product.htm): Yup, the U.S. Military is the last people you'd expect to see studying ergonomics. On the other hand they have a lot of people in various office jobs, and probably have seen the benefit of studying the workplace and reducing the damage to bodies done by poor ergonomics. In any case, what's there is a bunch of research papers. Similarly there is the Department of Defense Human Factors Engineering Technical Advisory Group.
Office Ergonomics Training (http://office-ergo.com/) - Information resource covering ergonomics in offices.
The Ergonomics Society (http://www.ergonomics.org.uk/) - an international organisation for professionals using knowledge of human abilities and limitations to design and build for comfort, efficiency, productivity and safety.
Occupational Safety & Health Administration - Ergonomics (http://www.osha.gov/SLTC/ergonomics/) -
the campaign for better seating (http://www.betterseating.org/) - has been organised to bring information about the importance of chair design to the attention of everyone.
Driving Ergonomics (http://www.drivingergonomics.com/) - your guide to being comfortable, safe and healthy, in and around your car.
The Posture Page (http://www.posturepage.com/) - Better Ways to Sit, Stand, Move & Present Yourself to the World
The International Ergonomics Association (http://www.iea.cc/) is the federation of ergonomics and human factors societies from around the world.
Healthy Computing (http://www.healthycomputing.com/) - providing unbiased information on ergonomics.
The National Institute for Occupational Safety and Health (NIOSH) (http://www.cdc.gov/niosh/homepage.html) is the federal agency responsible for conducting research and making recommendations for the prevention of work-related injury and illness. See Ergonomics and Musculoskeletal Disorders (http://www.cdc.gov/niosh/topics/ergonomics/)
Medline Plus: Ergonomics (http://www.nlm.nih.gov/medlineplus/ergonomics.html)