Wargames-etc

Some great plates, mostly in German, but a few gems in English (depending on your perspective!)  This site is growing constantly and is maintained by a real enthusiast that tries to constantly add resources.
 

Grosser-Generalstab

Lots of pictures, unfortunately all in German.  From what I can gather from Babel Fish, this gentleman has some old books of plates and is trying to get them all on the web.
 

Grosser-Generalstab(Prussian)

Another amazing site for a Prussian Uniforms.  Also in German, but easily understood by English speakers.
 

NYPLDigital Gallery

The New York Public Libraries own digital gallery of uniform plates.  A great resource if you have the time to sort through it.
 

French troops really aren't my bag, but this is an excellent and beautifully set out site.  It is in French, but you can get what you need if you only speak English.
 

This is a fantastic site for general information and the collection of plates available is growing by the week.  France, Sweden, Hanover, and Hesse-Kassel are all very well represented with color plates.  By the time you read this many more might be available. 
 

Here we have a gentleman with the ability to draw accurately, the desire to get it right, the knowledge to research, and the desire to blog it all for our entertainment.  If you have ever had the desire to make your own plates for the SYW period, you are only a few clicks away from making it happen.  Visit this site and see what is happening!