There's a script that takes a snapshot of your entire map, made by me(tm) (<- that's his actual username... or was, back then). You might be able to modify it to only capute what you currently see on the screen, but tit should definately give you a head start.
There's no default function for that, if that's what you were asking.
Another way to go might be to set all windows to invisible for a split second, then take your shot, then reenable it. A bit messy and possibly ugly, though.