Here is how to change the link in your header for your WP Canvas theme

gistfile1.txt

<a class="home-link" href="http://your-domain.com" rel="home">
	<?php if ( $logo_image = get_option( WORDPRESSCANVAS_PREFIX . 'logo_image' ) ) : ?>
		<h1 class="site-logo">
			<img src="<?php echo $logo_image; ?>" alt="<?php bloginfo( 'name' ); ?> - <?php bloginfo( 'description' ); ?>" />
		</h1>
	<?php endif; ?>
	<?php if ( get_option( WORDPRESSCANVAS_PREFIX . 'show_site_text' ) ) : ?>
		<h1 class="site-title"><?php bloginfo( 'name' ); ?></h1>
		<h2 class="site-description"><?php bloginfo( 'description' ); ?></h2>
	<?php endif; ?>
</a>