Drupal 6 ubercart customise cart page
You need to alter the default Ubercart's theming of the shopping cart form and increase the weight of "Remove" column so it is pushed to the end.
Add the following code to your theme's template.php file.

/**
 * Themes the uc_cart_view_form().
 */
function phptemplate_uc_cart_view_form($form) {

  // Increase the weight of Remove column, so it goes to the end.
  $form['items']['#columns']['remove']['weight'] = 100;

  // The rest of the code is default Ubercart's code you can see in:
  // theme_uc_cart_view_form() function in uc_cart.module.
  drupal_add_css(drupal_get_path('module', 'uc_cart') .'/uc_cart.css');

  $output = '&lt;div class="uc-default-submit"&gt;';
  $output .= drupal_render($form['update']);
  $output .= '&lt;/div&gt;';
  unset($form['update']['#printed']);

  $output .= '&lt;div id="cart-form-products"&gt;'
          . drupal_render($form['items']) .'&lt;/div&gt;';

  foreach (element_children($form['items']) as $i) {
    foreach (array('title', 'options', 'remove', 'image', 'qty') as $column) {
      $form['items'][$i][$column]['#printed'] = TRUE;
    }
    $form['items'][$i]['#printed'] = TRUE;
  }

  // Add the continue shopping element and cart submit buttons.
  if (($type = variable_get('uc_continue_shopping_type', 'link')) != 'none') {
    // Render the continue shopping element into a variable.
    $cs_element = drupal_render($form['continue_shopping']);

    // Add the element with the appropriate markup based on the display type.
    if ($type == 'link') {
      $output .= '&lt;div id="cart-form-buttons"&gt;&lt;div id="continue-shopping-link"&gt;'
               . $cs_element .'&lt;/div&gt;'. drupal_render($form) .'&lt;/div&gt;';
    }
    elseif ($type == 'button') {
      $output .= '&lt;div id="cart-form-buttons"&gt;&lt;div id="update-checkout-buttons"&gt;'
               . drupal_render($form) .'&lt;/div&gt;&lt;div id="continue-shopping-button"&gt;'
               . $cs_element .'&lt;/div&gt;&lt;/div&gt;';
    }
  }
  else {
    $output .= '&lt;div id="cart-form-buttons"&gt;'. drupal_render($form) .'&lt;/div&gt;';
  }

  return $output;
}