This is a very simple thing to do:
if(Mage::getSingleton('cms/page')->getIdentifier() == 'homepage' &&
Mage::app()->getFrontController()->getRequest()->getRouteName() == 'cms'
) : ?>rel="index,follow"
<?php endif; ?>>Black Rhino Media</a>
The ‘homepage’ identifier may be different for your particular site so amend as necessary.
This approach can help you to avoid getting a penalty from Google for linking to your site from every single page of every single website you build for your clients.