Open up showthreads.php
Find:

if ($avatarurl=="" or ($bbuserinfo[userid]>0 and !($bbuserinfo[showavatars]))) {
$post[avatar]="";
} else {
eval("\$post[avatar] = \"".gettemplate("postbit_avatar")."\";");
}

Add below:

//START GLOWING NAMES
if($post[usergroupid]==6) //Administrators
{
$glowcolor = '#0000FF';
$glowstrength = 5;
}
elseif($post[usergroupid]==5) //supermods
{
$glowcolor = '#33FF00';
$glowstrength = 4;
}
elseif($post[usergroupid]==7) //mods
{
$glowcolor = '#FF0000';
$glowstrength = 3;
}
elseif($post[usergroupid]==8) //Banned By Admins {
$glowcolor = '#FF9900';
$glowstrength = 2;
}
elseif($post[usergroupid]==9) //Members
{
$glowcolor = '#FFFF00';
$glowstrength = 0;
}
//END GLOWING NAMES

In postbit template:

$post[firstnewinsert
PUT CODE HERE
<smallfont>$post[usertitle]</smallfont><br>

<normalfont><b><div class="nf" style="width:100%;filter:Glow(color=$glowcolor, strength=$glowstrength);">
<font class="sf">&nbsp;</font><a href="member.php?s=$session[sessionhash]&action=getinfo&userid=$post[userid]" target="_blank">
$post[username]</a>
</div></b></normalfont>

I think this already exists doesn't it? The code is like the 'staff glowing in posts' hack which I've installed a while ago. Although yours does seem different in coding.

It exists yes, and I did that exact hack, and its just editing whats already there....

Good for giving it to the public!

Isnt that admin/functions.php? ;):D

yep sorry :D