how to sort by alphabet?

i have a template page which contains all my posts.
the list of posts is sorted by date, i want to sort it by alphabet of the post title
the code i have is this

<?php
$debut = 0; //The first article to be displayed
?>
<?php while(have_posts()) : the_post(); ?>
<h2><?php the_title(); ?></h2>
<ul>
<?php
$myposts = get_posts('numberposts=-1&offset=$debut');
foreach($myposts as $post) :
?>
<li><a href="<?php the_permalink(); ?>"><?php the_title(); ?></a></li>
<?php endforeach; ?>
</ul>
<?php endwhile; ?>

what can i do to sort it as alphabet?
thank you.