In place of creating your own mobile styles for your Joomla! website, there is also a free extension that allows you to provide a mobile version of your website with minimal effort. The extension is called MobileJoomla! and caters for a wide range of mobile telephones with Internet access, from iPhones to BlackBerry devices and other smartphones.
As ever, the disadvantage of using a Joomla! extension to provide your visitors with a mobile stylesheet is that it adds to the page load time, as even if the extension is not used, it must be loaded.