i found the following method to work:
in catalog.xml inside reference block “content”, after “product_list”, i added:
<block type="checkout/cart_sidebar" name="cart_sidebar" before="-" template="checkout/cart/sidebar.phtml"/>
in /app/design/frontend/default/TEMPLATENAME/template/catalog/category/view.phtml, after the productlisting php tags i added,
<?php echo $this->getChildHtml('cart_sidebar') ?>
other than adding some div styling to house the cart_sidebar, that was it.
i’m assuming my problem before what that i was trying to call the cart_sidebar in list.phtml, but when i went back and read my post, i realized that inside my layout file, i was setting it up inside view, not list.
to summarize, set up your content blocks in your layout file, then play close attention to where your content block falls so you reference it correctly in the template files.
anyway, i hope this helps someone out.