Resumen: Librería PHP para lectura y escritura de archivos .XLS .XLSX, en este caso se indica como integrar en CodeIgniter.

Descarga: https://github.com/PHPOffice/PHPExcel

+ Info:

• http://www.ahowto.net/php/easily-integrateload-phpexcel-into-codeigniter-framework
• http://www.jqueryeasy.com/2011/12/22/leer-archivo-excel-en-codeigniter/
• http://ellislab.com/forums/viewthread/187597/
• https://github.com/EllisLab/CodeIgniter/wiki/PHPExcel

application/libraries/Excel.php

<?php if ( ! defined('BASEPATH')) exit('No direct script access allowed');
/* 
 *  ======================================= 
 *  Author     : Muhammad Surya Ikhsanudin 
 *  License    : Protected 
 *  Email      : mutofiyah@gmail.com 
 *   
 *  Dilarang merubah, mengganti dan mendistribusikan 
 *  ulang tanpa sepengetahuan Author 
 *  ======================================= 
 */  
require_once APPPATH."/third_party/PHPExcel.php"; 
 
class Excel extends PHPExcel { 
    public function __construct() { 
        parent::__construct(); 
    } 
}

Uso en Controlador

//load our new PHPExcel library
$this->load->library('excel');
//activate worksheet number 1
$this->excel->setActiveSheetIndex(0);
//name the worksheet
$this->excel->getActiveSheet()->setTitle('test worksheet');
//set cell A1 content with some text
$this->excel->getActiveSheet()->setCellValue('A1', 'This is just some text value');
//change the font size
$this->excel->getActiveSheet()->getStyle('A1')->getFont()->setSize(20);
//make the font become bold
$this->excel->getActiveSheet()->getStyle('A1')->getFont()->setBold(true);
//merge cell A1 until D1
$this->excel->getActiveSheet()->mergeCells('A1:D1');
//set aligment to center for that merged cell (A1 to D1)
$this->excel->getActiveSheet()->getStyle('A1')->getAlignment()->setHorizontal(PHPExcel_Style_Alignment::HORIZONTAL_CENTER);
 
$filename='just_some_random_name.xls'; //save our workbook as this file name
header('Content-Type: application/vnd.ms-excel'); //mime type
header('Content-Disposition: attachment;filename="'.$filename.'"'); //tell browser what's the file name
header('Cache-Control: max-age=0'); //no cache
 
//save it to Excel5 format (excel 2003 .XLS file), change this to 'Excel2007' (and adjust the filename extension, also the header mime type)
//if you want to save it as .XLSX Excel 2007 format
$objWriter = PHPExcel_IOFactory::createWriter($this->excel, 'Excel5');  
//force user to download the Excel file without writing it to server's HD
$objWriter->save('php://output');