Mobile searches are becoming greater by the day. At first most may think that simply means more website traffic, which could be true. However it also means you may want to consider optimizing your site for those users. There is also the issue of assuring your content is found in search engines. For an excellent mobile phone primer and information about your content being found in search engines always turn to the best. That would be Google and their webmaster blog with a recent post about Making Websites Mobile Friendly.
Google Webmaster Article on Making Sites Mobile Friendly
I do suggest you follow that link above for a little background on mobile phones and mobile content. There is also information on how the Googlebot works, URL structure, and mobile sitemaps. They are always a wealth of information.