arba gali pabandyti paslepti nuo googliaus info :) ar kito boto. Kazkas 
panasaus....

<?php
   $crawlers = array(
     'Google'=>'Google',
     'MSN' => 'msnbot',
     'Rambler'=>'Rambler',
     'Yahoo'=> 'Yahoo',
     'AbachoBOT'=> 'AbachoBOT',
     'accoona'=> 'Accoona',
     'AcoiRobot'=> 'AcoiRobot',
     'ASPSeek'=> 'ASPSeek',
     'CrocCrawler'=> 'CrocCrawler',
     'Dumbot'=> 'Dumbot',
     'FAST-WebCrawler'=> 'FAST-WebCrawler',
     'GeonaBot'=> 'GeonaBot',
     'Gigabot'=> 'Gigabot',
     'Lycos spider'=> 'Lycos',
     'MSRBOT'=> 'MSRBOT',
     'Altavista robot'=> 'Scooter',
     'AltaVista robot'=> 'Altavista',
     'ID-Search Bot'=> 'IDBot',
     'eStyle Bot'=> 'eStyle',
     'Scrubby robot'=> 'Scrubby',
     );

function crawlerDetect($USER_AGENT)
{
     // to get crawlers string used in function uncomment it
     // it is better to save it in string than use implode every time
     // global $crawlers
     // $crawlers_agents = implode('|',$crawlers);
     $crawlers_agents = 
'Google|msnbot|Rambler|Yahoo|AbachoBOT|accoona|AcioRobot|ASPSeek|CocoCrawler|Dumbot|FAST-WebCrawler|GeonaBot|Gigabot|Lycos|MSRBOT|Scooter|AltaVista|IDBot|eStyle|Scrubby';

     if ( strpos($crawlers_agents , $USER_AGENT) === false )
        return false;

// pvz

$crawler = crawlerDetect($_SERVER['HTTP_USER_AGENT']);

if ($crawler )
{
    // paieskos botams $crawler galimi variantai jei noresi
}
else
{
     if (stripos( $_SERVER['HTTP_REFERER'], $crawler ) !== false ) {
     header( 'Location: www.tavopuslapis.lt' );
     die();
}
}