Hi Oleg,
I wanted to do the same thing. As it turns out, its really easy to do. Here's a couple examples.. you could also do a header redirect to a new page, hope this helps...
<?
if($HTTP_HOST == 'my.domain.com) {
echo "<title>welcome to my.Domain.com</title>";
exit;
}
if($HTTP_HOST == 'someother.domain.com) {
echo "<title>welcome to someother.Domain.com</title>";
exit;
}
?>