I think this is what you are looking for:

Code:
on *:TEXT:!addnews *:*:{
  var %limit = 8
  ;
  write news.txt $2-
  while ($lines(news.txt) > %limit) { write -dl1 news.txt }
  .notice $nick Added news item
}

on *:TEXT:!shownews:*:{
  .notice $nick News Headlines (oldest items first)
  .play -n $nick news.txt 500
}


Usage:
!addnews news item here
!shownews

To change the number of items that are maintained, change the limit number on line 2 (var %limit = 8).

-genius_at_work