RPM (Real Physical Media) is the first plugin of its kind. With the power of Real Media Library and Media File Renamer (free or Pro Version, both works) it allows you to change the physical media storage path and media URL. This can also have some SEO benefits. Do you know the wp-content/uploads folder? There, the files are stored in year/month based folders. This can be a very complicated and mass process, especially when you are working with a FTP client like FileZilla.