I don't know if this has been posted or not, but for those of y'all that create your own decals, I have the perfect website. You can download some of these images free, then once you use up some amount of bandwidth, you have to become a member, which is also free, it just takes a bit of filling out forms...anyways, they have paint shop pro images (these will also open in GIMP) of all kinds of national markings, unit badges for what appears to me to be *every* luftwaffe unit from WWII, as well as a smattering of other goodies. Check it out!
http://www.simmerspaintshop.com/forums/cat3.html
These are ridiculously high quality images, I wish I could thank whoever made them personally. I never even considered reference material from flight sim skinnners, LOL, who'd of thought? Enjoy, and if you know of more sites like these, by all means, please share.