One tool that I’ve found absolutely essential if you do any type of bulk importing or updating is MAGMI. It’s not a Magento extension but rather an independent database client that can import/update with incredible speed.
Here’s the description from the MAGMI website:
Magmi is a Magento Mass Importer developed as a magento DATABASE client, (ie not a magento extension) , that operates directly in SQL and is the result of a deep analysis of the Magento Database Model. The first magmi goal was catalog import & update.
it can create products or update an existing catalog and deal with HUGE data (Millions of products could be managed by magmi,but even above a few 1000’s , you’ll see the real difference with dataSlow)
Rather than repeat all the benefits, simply go to their site and check it out:
If you decide to install, I’d recommend creating a separate password protected directory to run it from.