fortkentgent

I got it.

<?php if (get_post_meta($post->ID, 'source', true) ) { ?>
				<h1><a href="<?php echo get_post_meta($post->ID, "source", $single = true); ?>" rel="external" title="External Link to <?php the_title(); ?>"><?php the_title(); ?></a></h1>
				<?php } else { ?>
                <h1><a href="<?php the_permalink() ?>" rel="bookmark" title="Permanent Link to <?php the_title(); ?>"><?php the_title(); ?></a></h1>
				<?php } ?>