Add this to your footers:
<script>
var Agent = new Array()
Agent[Agent.length]=["NAME","URL"];
tabs = "";for(Moose=0;Moose<Agent.length;Moose++){
//Created by Agent Moose (smcodes.smfforfree3.com)
tabs += "<td valign='top' class='maintab_back'><a href='"+Agent[Moose][1]+"'>"+Agent[Moose][0]+"</a></td>"
};
$(".maintab_back:contains(Logout) , .maintab_back:contains(Register)").after('<td class="maintab_last">&#'+'8195;</td><td class="maintab_first"></td>'+tabs);
</script>
Change NAME to whatever you want to call the tab. Put the URL link in where it says URL.
Make sure you have this js query line in your headers:
<script src="http://yourforum.smfforfree.com/jquery.js"></script>
Replace yourforum with your forum's subdomain and smfforfree.com with your smfforfree site such as smfforfree3.com
This will put a tab up where you see logout, search etc.