You'll probably have better luck posting this question in the armor section.
I would also recommend being more specific as to what exactly you want to paint. Color schemes depended on, among other things, type of armor, time of year, and theater of operations.
Take a little time to search the net looking for how people do their weathering techniques. They will typically outline what colors they use, as well as how to apply (and in some cases, remove) washes and weathering. The "Search the forums" box in the upper right helps, as do search engines like Yahoo! and Google.
I realize this is very vague, but I hope it helps.