use LWP::UserAgent;

$ua = LWP::UserAgent->new;

$ua->proxy("http", "http://proxy_host:proxy_port/");
    
my $req = HTTP::Request->new(GET => "http://www.google.com/");
my $res = $ua->request($req);

if ($res->is_success) {
    print $res->content;
} else {
     print "Bad luck this time\n";
}