alias chkconfig="chkconfig | perl -pe 'use Term::ANSIColor; s/\bon\b/color(\"green\").on.color(\"reset\")/ige;'"
or to permit passing an agrument:
function chkconfig(){
/sbin/chkconfig $* | perl -pe 'use Term::ANSIColor; s/\bon\b/color("green").on.color("reset")/ige;'
}