To import reviews in Magento
1.First go to www.magentocommerce.com and download the “Magento Connect extension”.
2. Then log in to your Magento administration account and go to your dashboard->System and scroll down to the option "Advanced Profiles."
3.Select "Advanced Customer Report Import". Then go to "Browse" and select a .csv file from your pc and click OK.
4. Select Import and wait. The file will be imported to the Magento dashboard.