wordpress theme post display Help

Hi,
i am currently working on a wordpress theme, and now i have come to a point where i need some help from more experienced people

Basically, the theme is done, but for now my posts display in 1 column like this:

Post title 1

textextext
textexttext

Post title 2

textextext
textexttext

Post title 3

textextext
textexttext

But i would like to make it so it displays posts in two columns, something like this:

Post title 1 Post title 2

textextext textextext
textexttext textextext

Post title 3 Post title 4

textextext textextext
textexttext textextext

Here is the code for posts i have for now, so anyone who could make me a working sample??
-current code:

Code:

<div id="blog">
        <?php if(have_posts()) : ?><?php while(have_posts()) : the_post(); ?>
         
        <div class="post">
        <h3><a href="<?php the_permalink(); ?>"><?php the_title(); ?></a></h3>
            <div class="entry">   
                <?php the_post_thumbnail(); ?>
                <?php the_content(); ?>
 
                <p class="postmetadata">
                <?php _e('Filed under&#58;'); ?> <?php the_category(', ') ?> <?php _e('by'); ?> <?php  the_author(); ?><br />
                <?php comments_popup_link('No Comments &#187;', '1 Comment &#187;', '% Comments &#187;'); ?> <?php edit_post_link('Edit', ' &#124; ', ''); ?>
                </p>
 
            </div>
 
            <div class="comments-template">
                <?php comments_template(); ?>
            </div>
    </div>
 
<?php endwhile; ?>
     
    <div class="navigation">  
        <?php previous_post_link('< %link') ?> <?php next_post_link(' %link >') ?>
    </div>
 
<?php endif; ?>
</div>