DO's can (and do) specialize in everything from Anesthesiology to Thoracic Surgery...as well as everything in between.
There are Osteopathic post graduate training programs in:
Anesthesiology
Cardiology
Child Psychiatry
Critical Care Medicine (adult)
Dermatology
Emergency Medicine
Family Practice
Gastroenterology
Geriatric Medicine
Hematology-Oncology
Infectious Disease
Internal Medicine
Nephrology
Neurological Surgery
Neurology
Obstetrics/Gynecology
Occupational Medicine
Opthalmology
Orthopedic Surgery
Otolaryngology
Pathology
Pediatrics
Physical Medicine & Rehabilitation
Osteopathic Manipulative Medicine
Plastic Surgery
Psychiatry
Pulmonary Disease
Radiology (Diagnostic)
Sports Medicine
Surgery (General)
Thoracic Surgery
Urology
Vascular Surgery
As another poster mentioned, DO students are able to enter the Allopathic Match program as well and match into MD residency spots, on top of having the option to pursue an Osteopathic residency.
To find a DO by name, specialty, or location, go to the following link:
<a href="http://directory.aoa-net.org/cfm/PublicSearch.cfm" target="_blank">http://directory.aoa-net.org/cfm/PublicSearch.cfm</a>
You can also look in the Yellow Pages for your area under "Physicians".
Good luck and feel free to post more questions that you may have.