Edit /templates/YOURTEMPLATE/header.tpl
Between <head> and </head> replace all the occurrences of
<title>
with
<title><!-- IF session.new_messages --> ({session.new_messages}) <!-- ENDIF -->
Please note that there is a space between the <!-- ENDIF --> and the next piece of code.
If a member has new message/s, a number in brackets will show in the tab, just like Facebook. Eg (2) UserName | DomainName
No matter which page of your site that a member is on, they will see a number if they have new messages. It will look something like this
[img]http://www.desperatesailors.com/cf/tab.jpg[/img]
