Magento – 1.9 – Add custom column to Sales Order Create Grid

use this code in Productspublisher.php

<?php
class Mage_Adminhtml_Block_Sales_Order_Renderer_Productspublisher extends Mage_Adminhtml_Block_Widget_Grid_Column_Renderer_Abstract
{
    public function render(Varien_Object $row)
    {                    

          $order=Mage::getModel('sales/order')->load($row->getData('entity_id'));              
        $str="";

        foreach($order->getAllVisibleItems() as $_item){  
        $product=Mage::getModel('catalog/product')->load($_item->getProductId());                    
            $str .= $product->getAttributeText('publisher')."<br>";
    }       

        unset($order);
        return $str;
    }
}
?>

Use 'frame_callback' property in addColumn. Below is the working code of fetching sku's in order grid.

    protected function _prepareCollection()
    {
        $collection = Mage::getResourceModel($this->_getCollectionClass());
        $this->setCollection($collection);
        return parent::_prepareCollection();
    }

    protected function _prepareColumns()
    {
        $this->addColumn('increment_id', array(
           'header' => Mage::helper('sales')->__('SKU'),
           'index' => 'increment_id',
           'frame_callback' => array($this, 'callback_skus'),
           'filter'    => false,
        ));

        $this->addColumn('real_order_id', array(
            'header'=> Mage::helper('sales')->__('Order #'),
            'width' => '80px',
            'type'  => 'text',
            'index' => 'increment_id',
        ));

        if (!Mage::app()->isSingleStoreMode()) {
            $this->addColumn('store_id', array(
                'header'    => Mage::helper('sales')->__('Purchased From (Store)'),
                'index'     => 'store_id',
                'type'      => 'store',
                'store_view'=> true,
                'display_deleted' => true,
            ));
        }

        $this->addColumn('created_at', array(
            'header' => Mage::helper('sales')->__('Purchased On'),
            'index' => 'created_at',
            'type' => 'datetime',
            'width' => '100px',
        ));

        $this->addColumn('billing_name', array(
            'header' => Mage::helper('sales')->__('Bill to Name'),
            'index' => 'billing_name',
        ));

        $this->addColumn('shipping_name', array(
            'header' => Mage::helper('sales')->__('Ship to Name'),
            'index' => 'shipping_name',
        ));

        $this->addColumn('base_grand_total', array(
            'header' => Mage::helper('sales')->__('G.T. (Base)'),
            'index' => 'base_grand_total',
            'type'  => 'currency',
            'currency' => 'base_currency_code',
        ));

        $this->addColumn('grand_total', array(
            'header' => Mage::helper('sales')->__('G.T. (Purchased)'),
            'index' => 'grand_total',
            'type'  => 'currency',
            'currency' => 'order_currency_code',
        ));

        $this->addColumn('status', array(
            'header' => Mage::helper('sales')->__('Status'),
            'index' => 'status',
            'type'  => 'options',
            'width' => '70px',
            'options' => Mage::getSingleton('sales/order_config')->getStatuses(),
        ));

        if (Mage::getSingleton('admin/session')->isAllowed('sales/order/actions/view')) {
            $this->addColumn('action',
                array(
                    'header'    => Mage::helper('sales')->__('Action'),
                    'width'     => '50px',
                    'type'      => 'action',
                    'getter'     => 'getId',
                    'actions'   => array(
                        array(
                            'caption' => Mage::helper('sales')->__('View'),
                            'url'     => array('base'=>'*/sales_order/view'),
                            'field'   => 'order_id',
                            'data-column' => 'action',
                        )
                    ),
                    'filter'    => false,
                    'sortable'  => false,
                    'index'     => 'stores',
                    'is_system' => true,
            ));
        }
        $this->addRssList('rss/order/new', Mage::helper('sales')->__('New Order RSS'));

        $this->addExportType('*/*/exportCsv', Mage::helper('sales')->__('CSV'));
        $this->addExportType('*/*/exportExcel', Mage::helper('sales')->__('Excel XML'));

        return parent::_prepareColumns();
    }

   public function callback_skus($value, $row, $column, $isExport) {
        $increment_id = $value;
        $_order = Mage::getModel('sales/order')->loadByIncrementId($increment_id);
        $_items = $_order->getAllItems();
        $skus="";
        foreach ($_items as $item) {
                if($item->getData('product_type') == "simple"){
                    $skus .= $item->getSku()."<br/>";
                }
        }
        return $skus;
    }