Short answer:   :syntax on   in command mode.

Judging by your "make install" output (which happened to get posted in a separate thread), you're on a Solaris box. You have choosen MOTIF as your gvim GUI. Syntax hilighting looks a bit better in gvim IMHO, so you might want to try that. Well, I might aswell post my $HOME/.vimrc file too:

version 5.0
set nocompatible
let cpo_save=&cpo
set cpo=B
map! <S-Insert> <MiddleMouse>
map Q gq
map <S-Insert> <MiddleMouse>
syntax on
set background=light
set guifont=6x13
highlight Normal guibg=white guifg=black
set guioptions-=rtT

set t_me=ESC[0;0;37m
set t_mr=ESC[0;1;33;44m
set t_md=ESC[1;33m
set t_se=ESC[1;37;40m
set t_so=ESC[1;32;45m
set t_ue=ESC[0;1;37m
set t_us=ESC[1;32m
[download]

Where ESC is to be replaced by the "real" ESC code ofcourse.

One of VIM's greatest features is the rich "online" help. It explains everything about everything. You can access it by typing :h <searchtext> in command mode.