The simple way:
At navbar:
Find:
Code:
<div class="body_wrapper">
<div id="breadcrumb" class="breadcrumb"<vb:if condition="THIS_SCRIPT == 'index'"> style="display:none;"</vb:if>>
<ul class="floatcontainer">
<li class="navbithome">You are at: <a href="index.php{vb:raw session.sessionurl_q}" accesskey="1"><img src="{vb:stylevar imgdir_misc}/navbit-home.png" alt="{vb:rawphrase home}" /></a></li>
{vb:raw navbits.breadcrumb}
{vb:raw navbits.lastelement}
</ul>
Which can be found below:
Code:
<!-- closing div for above_body -->
You can add: "You are at:" at this line:
Code:
<li class="navbithome">You are at: <a href="index.php{vb:raw session.sessionurl_q}" accesskey="1"><img src="{vb:stylevar imgdir_misc}/navbit-home.png" alt="{vb:rawphrase home}" /></a></li>
And it works for me

. Home icon is in the way though if that doesn't bother you. But it can be easily removed by removing the code.
Code:
<img src="{vb:stylevar imgdir_misc}/navbit-home.png" alt="{vb:rawphrase home}" />
More official way:
Now, if you want something more "official".. Go to: AdminCP -> Languages & Phrases -> Phrase Manager -> Add new Phrase
Leave the type and product as it is, and as for the "Varname", use something that is related to what you want. For example, for the sake of it lets use "you_are_at" (with the _) and in the Text box, type in You are at:. So, you'll be having this:
Phrase Type: GLOBAL
Product: vBulletin
Varname: you_are_at
Text: You are at:
You can ignore the translation box if you don't use any translation files other than English. Now, go back to the navbar template and replace:
Code:
<li class="navbithome">You are at: <a href="index.php{vb:raw session.sessionurl_q}" accesskey="1"><img src="{vb:stylevar imgdir_misc}/navbit-home.png" alt="{vb:rawphrase home}" /></a></li>
With
Code:
<li class="navbithome">{vb:rawphrase you_are_at} <a href="index.php{vb:raw session.sessionurl_q}" accesskey="1"><img src="{vb:stylevar imgdir_misc}/navbit-home.png" alt="{vb:rawphrase home}" /></a></li>
And you are done

.