Google Analytics now tracks mobile websites and mobile apps so you can better measure your mobile marketing efforts. If you're optimizing content for mobile users and have created a mobile website, Google Analytics can track traffic to your mobile website from all web-enabled devices, whether or not the device runs JavaScript. This is made possible by adding a server side code snippet to your mobile website. Of course, you can still track visits to your regular website coming from high-end, Javascript enabled phones.

This is a Services Addon Module, and you need Services 6.x-2.x.

After installation, you must go to /admin/settings/gaservice to enter your Google Analytics account number

Change of Implementation
The original server side script shipped by Google only works for "Browsers". I modified the implementation so it can work with any "Client". The original script is ga.php, which is not used. The modified version is ga_mod.php.