my $shell = Win32::OLE->new('Shell.Application');
my @ies = grep { $_->FullName =~ /iexplore\.exe$/ } in $shell->Windows
+;

foreach $ie (@ies){#

    eval{
        $ie->{document}->getElementById("PUT THE ID OF AN ELEMENT THAT
+ IDENTIFIES THE PAGE YOU'RE LOOKING FOR HERE");
        $IEWindowYouAreLookingFor = $ie;
    };#end eval

}#END FOREACH
[download]

The way it works, if the element you're looking for isn't there the call to getElementById throws an error and the line:

$IEWindowYouAreLookingFor = $ie;

never executes. Otherewise the line runs and $IEWindowYouAreLookingFor gets set to point to the $ie window you're looking for. Use the Microsoft IE Developer toolbar to track down the IDs of stuff on the page.

This doesn't work if the end user has mulitple pages from the same site up. I don't know any way to check if the page has focus...