There are so many people now using mobile devices to view websites that you may need to consider if your site not only looks ok but is also still functioning correctly when viewed on these types of devices.
Creating a mobile friendly version of your site will not only allow you to retain more visitors which in turn means custom, but can actually help towards your visibility on the search engines. This is because search engines like Google like to promote websites that give their users the best experience and therefore will favour those sites that can offer a mobile friendly site.
There are many ways to create a mobile version of your website but most of it can be achieved simply by improving the existing code that is there.
If you wish to take things a step further you could actually have a mobile version of your site created that is stand alone to the main website. This will normally feature your main content / areas of the site in a very easily accessible way.