<p>How can I rename a Virtual Directory (or Web Application) in IIS 6.0/7.0 using VBScript?</p>

I assume you want to use a local shell script.
Try PowerShell, I think IIS7 has introduced
new administration tools
that look quite powerful. I
think
you could also use these scripts to manage IIS remotely via WMI.
It shouldn't be any more complicated then VBScript.
Another way would be to use VBScript to edit the IIS configuration files or create an
administration object
, but that doesn't really seem to be the way to go about it.
Hopefully this helps.