Travel Health

Smart Traveller Australian government site with current security alerts and general travel advice by region. Not for vaccination or disease advice.
The Travel Doctor Australian commercial site with links to local travel medicine clinics. Also has broad destination specific immunisation and disease advice. Often your local doctor can provide all your immunisation and other medication needs. 
CDC Destinations American site, Centre for Disease Control. This sections gives updated info on vaccine requirements by region, as well as latest outbreaks of disease.
CDC travel advice  This sections gives information on how to stay healthy, how to get medical care, possible disease risks not covered by vaccinations and more.
CDC Diseases  This sections gives updated info on the consequences of various diseases and added measures to avoid illness.
Holidays with Kids An Australian Commercial site related to the magazine of the same name with tips for travel, destinations and more.