Granting API custom/full access role in Magento 1.6.2 (Web Services > Roles) simply doesn't work.
How to we fix it?

Copy app/code/core/Mage/AdminHtml/Block/Api/Tab/RolesEdit.php

To: app/code/local/Mage/AdminHtml/Block/Api/Tab/RolesEdit.php

Inside, place the following:

class Mage_Adminhtml_Block_Api_Tab_Rolesedit extends Mage_Adminhtml_Block_Widget_Form {

    public function __construct() {
        parent::__construct();

        $rid = Mage::app()->getRequest()->getParam('rid', false);

        $resources = Mage::getModel('api/roles')->getResourcesList();

        $rules_set = Mage::getResourceModel('api/rules_collection')->getByRoles($rid)->load();

        $selrids = array();

        foreach ($rules_set->getItems() as $item) {
			if (array_key_exists(strtolower($item->getResource_id()), $resources)
                           && $item->getApiPermission() == 'allow') {
                $resources[$item->getResource_id()]['checked'] = true;
                array_push($selrids, $item->getResource_id());
            }
        }

        $this->setSelectedResources($selrids);

        $this->setTemplate('api/rolesedit.phtml');
    }
}

If for some reason you have list of products skus, and for each you need to fetch out it's name,
you will better not use the old way of
$pname = Mage::getSingleton("catalog/product")->load(Mage::getSingleton("catalog/product")->getIdBySku($productSku))->getName();

because it will slow up dramatically your site.
Better use the following piece of code:

<?php

$productSku = 'sku1';

$pname = Mage::getSingleton("catalog/product")
	    		->getCollection()
	    		->addFieldToFilter('sku', $newpsku)
	    		->addAttributeToSelect('name')
	    		->load()
	    		->getFirstItem()
	    		->getName();

To find out the SQL query Magento uses to retrieve a specific collection, just do the following:

Let's say you would like to know what query is used to get a product collection - go to your debugging area (or maybe some phtml file), and paste following code:

$_productCollection = Mage::getResourceModel("catalog/product_collection");
$_productCollection->load(true);

Passing "true" as a parameter to the load function, will print out the query that Magento uses to retrieve the items for the collection.