When trying to increase the rankings of a website, one of the many methods used to build a natural back link profile is by far directory submissions.
This not only helps towards a good back link profile but also DOES help with rankings. Some directories are "no-follow" some are "do-follow", aiming for a mix of both helps keep things looking natural in the eyes of the search engines. By no means are directory submissions the be all and end all to increasing rankings, however providing you research and seek quality directories with a high PR, directory submissions are a worthwhile process. Another point to mention is, ensure you keep the website URL, address details of the company and contact number consistent.