show all posts within category

I am currently using this code in single.php:

<?php $temp_query = $wp_query; ?>
<?php query_posts('cat=3&showposts=100'); ?>
<?php while (have_posts()) : the_post(); ?>

<li class="static"><a>" rel="bookmark" title="Permanent Link to <?php the_title(); ?>"><?php the_title(); ?></a>

<?php endwhile; ?>
<?php $wp_query = $temp_query; ?>

However, I need this to be dynamic for each of my three categories, but it’s defined in the loop as “cat=3”. I am using this code to return the category id:

<?php echo get_query_var( ‘cat’ ); ?>

Is there a way to merge the two pieces and build a piece of code that will check the category and then return only the posts in that category?

Thanks.