Wordpress Sidebar Messing up in IE

If you check out my site in IE - www.mintyferret.com, you'll see that the right-most sidebar is pushed down. View the site in firefox to see how it should look like. I'm not very familiar with 'Wordpress code' and I'm having a bit of trouble pinpointing the problem, help would be much appreciated!

Here's the code for the sidebar:

<div id="sidebar">

        <?php if (is_home()) { $check_home = '1'; } else { $check_home = '0'; } ?>

       

        <div class="sidebar_left">

            <ul>

                <li>

                    <?php include('adsense_sidebar.php') ?>

                </li>

               

                <?php if ( !function_exists('dynamic_sidebar') || !dynamic_sidebar(1) ) : ?>

       

                <?php endif; ?>

            </ul>

        </div>



        <div class="sidebar_right">

            <ul>

            <?php if ( !function_exists('dynamic_sidebar') || !dynamic_sidebar(2) ) : ?>

                <li>

                    <?php include (TEMPLATEPATH . '/searchform.php'); ?>

                </li>

           

                <!-- <?php wp_list_pages('title_li=<h2>Pages</h2>' ); ?> -->

               

<center><?php if (function_exists('useronline')): ?>

   <li>

      <ul>

         <li><div id="useronline-count"><?php get_useronline(); ?></div></li>

      </ul>

   </li>

<?php endif; ?>

</center>

                           

                <li><div id="side"><h2>Categories</h2></div>

                    <ul>

                    <?php wp_list_cats('sort_column=name&optioncount=1&hierarchical=0'); ?>

                    </ul>

                </li>

   

                <li>

        <h2><div id="side">Recent Posts</div></h2>

                <ul>

                    <?php query_posts('showposts=10'); ?>

                    <?php if (have_posts()) : while (have_posts()) : the_post(); ?>

                    <li><a href="<?php the_permalink() ?>"><?php the_title() ?></a></li>

                    <?php endwhile; endif; ?>

                </ul>

                </li>



<li>

<h2><div id="side">Pages</div></h2>

<ul><a href="http://mintyferret.com/request-a-tutorial/">Contact</a><br>

<a href="http://mintyferret.com/mintyferret-usage-license/">Usage License</a></ul>

</li>



                    <li>

        <h2><div id="side">Archives</div></h2>

                <ul>

                               

                <?php wp_get_archives('type=monthly'); ?>

                </ul>

                </li>

               

        <li><h2><div id="side">Affiliates</div></h2>

<ul>



<a href="http://www.photoshop-pack.com" title="Free adobe photoshop tutorials" target="blank">Photoshop Tutorials</a>

<br><a href="http://www.freshtuts.com" alt="Fresh Tutorials" target="blank"><a href="http://www.freshtuts.com">Fresh Tuts</a>

<br><a href="http://mintyferret.com/affiliates/">View All/Apply</a>





</ul>

</li>      


<li>
                <ul>

                <center><a href="http://mintyferret.com/request-a-tutorial/"><img src="http://mintyferret.com/wp-content/themes/default/images/request.gif"></a><center>

                </ul>

                </li>





                    <?php /* If this is the frontpage */ if ($check_home == '1') { ?>         

                    <?php get_links_list(); ?>

                   



                   

                    <!-- <li><h2>Meta</h2>

                    <ul>

                        <?php wp_register(); ?>

                        <li><?php wp_loginout(); ?></li>

                        <li><a href="http://validator.w3.org/check/referer" title="This page validates as XHTML 1.0 Transitional">Valid <abbr title="eXtensible HyperText Markup Language">XHTML</abbr></a></li>

                        <li><a href="http://gmpg.org/xfn/"><abbr title="XHTML Friends Network">XFN</abbr></a></li>

                        <li><a href="http://wordpress.org/" title="Powered by WordPress, state-of-the-art semantic personal publishing platform.">WordPress</a></li>

                        <?php wp_meta(); ?>

                    </ul>

                    </li> -->

                <?php } ?>

            <?php endif; ?>

            </ul>

        </div>

        <div style="clear:both;"></div>

    </div> 

HTML:

Thanks for taking a look!

 

Does anyone have any ideas? I'm checking it in IE 6 and the right-most sidebar is still being 'pushed' underneath the middle 'bar'.