well... I haven't checked it completely cross browser yet but it does work IE 5.5, IE6 & Firefox (EDIT: just checked Opera 7 & NS7) PC with no extranious markup at all, like so:
Step 1.
open header.php and Find:
<div class="inbox">
<div><?php echo $pun_config['o_announcement_message'] ?></div>
</div>
as you can see the "announcement bar" already has a parent element it just isn't named for some reason. So you need to give that element an id like so:
<div class="inbox">
<div id="announce-bar"><?php echo $pun_config['o_announcement_message'] ?></div>
</div>
Step 2.
open the css file for your forum's style and at the bottom add these three rules:
#announce-bar {
width: 100%;
overflow: auto;
}
#announce-left {
float: left;
width: 49%;
}
#announce-right{
float: right;
width: 50%;
}
Step 3.
In Administration > Options > Announcement message enter:
<div id="announce-left">this is left</div>
<div id="announce-right">this is right</div>
substituting your messages where appropriate, of course.
That will give you an announcement bar with left/right divisions that is still 100% semantic with no inline style declarations to muddy it up, and no meaningless divs used to hack the presentation into place.