Just as an example, here is(are) the relevant line(s) from my .kshrc
Code:
export PS1='\[^[[1;36m\]\u\[^[[1;37m\]@\[^[[1;32m\]\h\[^[[0;34m\]\
(\l)\[^[[0m\]:\[^[[0;31m\]\w\[^[[0m\]\$ '
I highly suggest you do a Google search for color ksh prompts for more info.