I have the good fortune to be working currently at Merlin, an international aid and development charity. Its not the biggest of the charities working in this area but it has carved out a reputation as being pretty good on its feet in an emergency (we were in Haiti soon after the earthquake) whilst also hanging around long enough to help put more durable arrangements in place in those countries that need it most.
Sustainable healthcare provision requires properly trained health workers. Without them it will simply fall apart. So we are currently campaigning for world leaders to step up to the plate and commit to having properly trained health workers in those countries that need it most.
You can go the campaign page here. Read the stories about people working in some of the toughest countries in the world and then decide whether the campaign is worth supporting . It costs nothing to add your name to the petition but if the campaign has whetted your appetite and you wish to find out how you can donate just follow the links to the main Merlin site.