Ncurses and color

Hi all,

I'm looking to write a program using Ncurses and I have a question
about colours (or colors if you are in the US).

On my machine (latest Ubuntu) I have libncurses version 5.6 and I
am running my test program inside an xterm (version 229). With this
setup, the ncurses function can_change_color returns false, but I
find the default colours are somewhat boring.

However I know I can get all sorts of interesting colors in programs
like Vim and GNU Screen. I've had a preliminary look at the sources
to these programs, but its not immediately obvious how they achieve
them.

Anyone have any clues to impart?

Thx,
Andrew J. Hunter