I stumbled across this snipet of php code today and thought many of you could put it to good use. To summarize, it will immediately alert you to the arrival of Googlebot via email. This is assuming of course you have sendmail, qmail, etc. configured.
if(eregi("google",$HTTP_USER_AGENT))
{
mail("user@yourdomain", "Googlebot detected", "Google has crawled yourdomain.com");
}