A Comparison of Methods for Building #Mobile-Optimized Websites
▻http://sixrevisions.com/mobile/methods-mobile-websites
Google advocates creating responsive web designs, while Jakob Nielsen, a renowned usability consultant, endorses the creation of dedicated mobile sites (but he was subsequently slammed by some web designers).
A third option is also gaining in popularity, where the web server renders the appropriate HTML and CSS from the same URL depending on the device a web page on the site is being requested from (which has been referred to as responsive design + server side components).