Due to popular demand ^^, here is a hello world example:

use warnings;
use strict;
use Template;

# create Template object
my $ttt = Template->new();
    
# define template variables for replacement
my $replacements = { name => "holli" };
my $template = join ("", <DATA>);

# process input template, substituting variables and save it to disk
$ttt->process( \$template, $replacements, "output.xml") || die $templa
+te->error();

#call fop and translate xml file to pdf
system "d:\\fop-1.0\\fop.bat -fo output.xml -pdf output.pdf"

__DATA__
<?xml version="1.0" encoding="iso-8859-1"?>
<fo:root xmlns:fo="http://www.w3.org/1999/XSL/Format">
    <fo:layout-master-set>
        <fo:simple-page-master master-name="my-page">
            <fo:region-body margin="1in"/>
        </fo:simple-page-master>
    </fo:layout-master-set>

    <fo:page-sequence master-reference="my-page">
        <fo:flow flow-name="xsl-region-body">
            <fo:block>Hello, [% name %]!</fo:block>
        </fo:flow>
    </fo:page-sequence>
</fo:root>
[download]

Instead of running fop via system, you might also look at XML::ApacheFOP.