*Disclaimer* Although advice on the forums is given with every intention of helping, no one posting on this site is a qualified herp vet. Nothing can take the place of the knowledge/expertise of one. When in the slightest doubt, and in emergencies the quicker the better, seeking the advise of a herp vet is the wisest thing to do.
Turtles are pets just like dogs, cats and other animals. Please don't shortchange them with less care than they deserve.
In medical emergencies or to find a qualified veterinary professional for any other reason, try the following links:
www.anapsid.org/vets/index.html#vetlist (includes other countries as well)
http://www.tortoise.org/general/vetlist.html (for California)
www.herpvetconnection.com (includes worldwide info as well)