European Dermato-Epidemiology Network (EDEN)
http://orgs.dermis.net/content/e02eden

International Dermato-Epidemiology Association (IDEA)
http://ebderm.org/ and click on IDEA Corner

British Association of Dermatologists (BAD)
http://www.bad.org.uk

UK Dermatology Clinical Trials Network
www.ukdctn.org/home/

Cochrane Skin Group
www.nottingham.ac.uk/csg

Skin Conditions Specialist Library
www.library.nhs.uk/skin