Dean's Permalinks Migration

Dean's Permalinks Migration plugin allows you to change your website's permalinks structure without losing the link juice coming in to your pages from the backlinks you have already built. If you set up your website before you knew anything about SEO and have the URLs that contain only page or post IDs rather than keywords, you'll benefit from using this plugin when you migrate to more search-friendly URLs. The plugin is very simple to use. Just download it from http://wordpress.org/extend/plugins/permalinks-migration-plugin-for-wordpress/ and install it. Then go to the plugin settings and type in your old permalink structure. Now edit the site's permalink structure to the new format. That's all there is to it.