This page describes modern military vehicle camouflage schemes. There are dozens of links and a ton of information. Essential stuff for anyone painting modern military miniatures.
Mike Cooper has a web page with useful information on World War Two vehicle camouflage. IIt includes text descriptions, as well as a virtual “paint chip” gallery.
Here’s a nice tutorial on painting tiger stripe camouflage.
sixtwentyeight blog has a tutorial on painting fallschirmjager camouflage.
Santa Cruz Wargamer has a tutorial on painting camouflage on a Tau vehicle.