[powerful_rogue]

Managed to get it working.

<if condition="$post[icqicon] OR $post[aimicon] OR $post[msnicon] OR $post[yahooicon] OR $post[skypeicon] OR $post[field6]"><div class="nzbpostbit">$post[icqicon] $post[aimicon] $post[msnicon] $post[yahooicon] $post[skypeicon] <!-- Facebook display start -->
<if condition="$post[field6]"><a href="http://www.facebook.com/profile.php?id=$post[field6]" alt="View my Facebook" target="_blank">
<img src="images/misc/facebook.gif" border="0"></a></div>
</if><!-- Facebook display end --> </div></if>
</div>

I had to add the bolded bit into the code, otherwise the facebook icon would only show if someone had MSN/ICQ etc