<?php if($this->canShowBlock()): ?>
<div class="block block-layered-nav">
    
    <div class="block-content">
        <?php echo $this->getStateHtml() ?>
        <?php if($this->canShowOptions()): ?>
            <p class="block-subtitle"><?php echo $this->__('Quick Product Finder') ?><p>
            <dl id="narrow-by-list">
                <?php $_filters = $this->getFilters() ?>
                <?php foreach ($_filters as $_filter): ?>
                <?php if($_filter->getItemsCount()): ?>
                <?php $__tcc=$this->__($_filter->getName());?>
                    <dt class="<?php echo "up_dt".$__tcc;?>">
                    <?php echo $__tcc;?>
                    </dt>                    
                   <dd class="<?php echo "up_dd".$__tcc;?>">
                   <?php echo $_filter->getHtml() ?>
                  </dd> 
                <?php endif; ?>
                <?php endforeach; ?>
            </dl>
            <script type="text/javascript">decorateDataList('narrow-by-list')<script>
        <?php endif; ?>
    </div>
</div>
<?php endif; ?>

http://www.magentocommerce.com/boards/viewthread/28220/P30/#t268687

template     catalog->layer->view.phtml

disable certain filter via css

magento

PHP