[CentOS] Apache default charset

Hi , i'm using centos spanish version 4.4, i have installed phpnuke
spanish , but i think that apache is showing a strange character � ,
when phpnuke (and other php and html pages) shows the ñ or
á but in spanish way (ñ and á), i would like to know if it is
possible changue configuration of apache to show this charactes to the
right way

Thanks