#!c:/perl/bin/perl -w
$|++;

use strict;
use CGI::Simple;
use URI::Escape;

my $CGI = CGI::Simple->new();

# save your copy of the information here
# using whatever method you prefer


# now we redirect the user to the 3rd party with the data
my $query = join(
   ';', map {
      uri_escape($_) . '=' . uri_escape($CGI->param($_))
   } $CGI->param()
);

print $CGI->redirect(
   'http://their.server.com/foo/bar.pl?' . $query
);