SEO Friendly URLs in our Zen Cart Store Please?

Hi, We just need our product URL's to be more SEO optimised, so instead of /[login to view URL] we would prefer it to be something more like this /[login to view URL] Coffee Taffeta Ribbon Woven Edge 10mm 15mm 25mm However, we would still need the original links to work correctly as there will be thousands of links we've emailed to our customers and they need to be able to still click on the URL's with the dynamic (existing) URL's. I understand there are already free mods than you should just have to install. I've tried this in the past and failed miserably, usually just white screens the site.