Featured posts code problem

Im new to WP and Im not real sure how to work with the loop. I am trying to display featured posts in the sidebar with this code:

<?php
    query_posts('cat=5');
    $url = get_permalink();
    while(have_posts()){
    the_post();
    $image_tag = wp_get_post_image('return_html=true');
    $resized_img = getphpthumburl($image_tag,'h=168&w=168&zc=1'); 

    $title = $post->post_title;

    echo "<ul class='left_featured'>";
    echo "<li><a href='";
    echo $url;
    echo "'><img src='$resized_img' width='168' height='168' ";
    echo "'/></a></li>";
    echo "<li><a href='";
    echo $url;
    echo "'/>";
    echo $title;
    echo "</a></li></ul>";
    echo "";
    };
    ?>

This gives me all sorts of crazy outputs, text from random posts, images, etc…Its supposed to output a list of images and titles for all of the posts in a certain category. Any help would be really appreciated.

Oh yeah, I am using a plugin that resizes images on the fly, thats what the the wp_get_post_image/getphpthumburl business is.