OK, first, let's make it clear. Do you want to change background and foreground colors in a terminal emulator _under X_ (in GUI, like KDE or GNOME), *or* do you want to change background/foreground in bare console, without X?
If former, you can try things like
(quite a painful combination, but just to give you the idea
If the latter, you have two ways of going about it.
First, if you're using framebuffer for the console, you should read this thread. Read it to the end. http://osdir.com/ml/linux.fbdev.user.../msg00008.html
If you don't use the framebuffer, then the prompt how-to is actually the only way you can have different colors.