use CGI::Cookie;
my %cookies = fetch CGI::Cookie;
my @userinfo;

if(check_login() && not validate_login() )
{
 logout_user();
} else {
 my $sth = $db->prepare("SELECT * FROM sites WHERE webmaster_email=? AND webmaster_url=? LIMIT 1");
 $sth->execute($cookies{'email'}, $cookies{'url'} ) or die "Can't execute statement: $DBI::errstr";  
 $userinfo = $sth->fetchrow_hashref;
}

#...
# später:
use CGI;
print 'URL: ', CGI::textfield( 'url', $userinfo->{'domain'} ), 
 CGI::br(), 
 'E-Mail: ', CGI::textfield( 'email', $userinfo->{'webmaster_email'} );