the_excerpt – how do I add link to show rest of post?

Hello,

I would like to show an excerpt of my posts and have a link for the user to see the full post.

I can show just the excerpt but don’t know how to add a link to show the full post. Any ideas?

<?php the_excerpt('<p class="serif">Read the rest of this entry &raquo;</p>'); ?>

^ that is what I use to show the excerpt but the ‘Read the rest of this entry »’ does not display, just the […]

Thanks