In header.php change:
<div id="branding" role="banner">
to
<div id="branding" role="banner" onclick="location.href='http://www.yourdomain.com/';" style="cursor: pointer;">
Decoding the Secrets of WordPress
In header.php change:
<div id="branding" role="banner">
to
<div id="branding" role="banner" onclick="location.href='http://www.yourdomain.com/';" style="cursor: pointer;">