If you want to display related products in Product view page Try adding
<block type="catalog/product_list_related" name="catalog.product.related" as="related" template="catalog/product/list/related.phtml"/>
under the
<block type="catalog/product_view" name="product.info" template="catalog/product/view.phtml">
like below in the catalog.xml
<reference name="content">
<block type="catalog/product_view" name="product.info" template="catalog/product/view.phtml">
<block type="catalog/product_list_related" name="catalog.product.related" as="related" template="catalog/product/list/related.phtml"/>
</block>
and in your themes product view.phtml
add code
<?php echo $this->getChildHtml('catalog.product.related') ?>
where you want to display related products