I'm looking to do the following:
If a user has came from google I want to display a different msg to the one shown on my site if they have came from anywhere else or if they have actually typed the url in.

I know I need to do soemthing similar to the following:

<?php if($_SERVER['HTTP_REFERER']!="http://www.google.co.uk"){
    echo this;
} ?>
All the refering url's from google will be different depending on what the user searched for in google so how would I go about checking to see if just the word google was conatined in the reffering url and not a specific url?

As always any help much appreciated.