For the past few months, we have been looking into ways to help our clients optimize their web sites for the mobile world. The ever-increasing popularity of web-accessible mobile phones is motivating a swift revolution for such "mobification."
In the past, the best way for optimizing a Drupal site for the mobile would be to use the Mobile Theme and use Domain Access. This would allow you to build a site such that m.YourSite.com will go to the site with the mobile theme.
However, there is a new tool available which allows for the simple optimization of web sites for the mobile world. This tool is called Mobify.me. With this tool, you can mobify your Drupal site in a few easy steps:
1) Enter the URL for your web site;
2) Select the content areas in the web site screen shot which you would like to show on the mobile device;

3) Tweak the CSS as it fits based on the emulated iPhone/Mobile view of the selected content areas;