If you work (or have been trained) in a medical field and are interested in volunteering some of your time and talent in Haiti you may inquire at these organizations.
International Medical Corps
http://imcworldwide.org
310-826-7800
Medical Teams International
http://medicalteams.org
503-624-1000
Need to complete the online application process.
Partners in Health
http://pih.org
617-432-5300 (fax) fax in CV information
Hands on Disaster Response
hodr.org/volunteer-info/