Many of these websites have fairly general information useful to skinners. The more specific stuff relates to my own areas of interest, Allied aircraft, naval in particular.
If you know of any other sites useful to skinners please add them to this thread together with a short description.
The Skin Department: http://www.ah-skins.com/index.phpLucull's site is invaluable for AH2 skinners. Upload your latest creation for others to try, or download other players' skins before they become available in the game. Also includes AH skinning forums and FAQs on skinning.
Skinner's Heaven: http://www.1java.org/sh/Skinning site dedicated to IL2 skinning, but useful for tutorials, colours and markings sections.
Urban Fredriksson's Color Reference Charts: http://www.ipmsstockholm.org/colorcharts/colorcharts.aspLot's of military colour references but no RGB conversions. Useful as a second source to compare to Skinner's Heaven.
Modelling Madness: http://modelingmadness.com/The decal and kit reviews are a very good source of skinning data.
HyperScale Aircraft Galleries http://www.hsgalleries.com/gallery04/galleries_air2004.htmPlastic kit gallery, good source of ideas for colour schemes and weathering.
Wing's Palette: http://wp.scn.ru/camms/archive/ww2_fighters/0082/index2.shtml?0082An aircraft profile archive, another good source of data.
Web-Birds: http://www.web-birds.com/USAAF squadron site. Has lots of aircraft photos of USAAF aircraft, together with squadron histories and stories.
IPMS UK Fleet Air Arm Special Interest Group: http://www.faasig.netfirms.com/Modeller's site for Royal Navy FAA aircraft. Includes photos, model reviews and profiles of FAA aircraft.
Fleet Air Arm Archive: http://www.fleetairarmarchive.net/Squadrons/700-1800_SquadronIndex.htmlProfiles and squadron histories of FAA aircraft.
Air of Authority - A History of RAF Organisation: http://www.rafweb.org/Menu.htmSquadron histories, photos, markings and lots of profiles for RAF aircraft.
B-24 Best Web: http://www.b24bestweb.com/Default.htmSite dedicated to USAAF B-24 Liberators. Lots of noseart photos indexed alphabetically.
RAF Liberator Squadrons http://www.acseac.co.uk/gallery/index.php?action=showgal&cat=1RAF Liberator photo gallery. (This site is a bit slow.)
Corsair, F4U, The Bent Wing Bird: http://users.skynet.be/bk317032/Part_Corsair_Plane/Menu/openmenu_JDS2_F4U.htmLots of profiles and photos of F4Us.