Maxaud

This plugin allows you to define different CSS rules that get loaded into the page’s for specific devices.
Includes checks for 18 different tablet options and 13 different phone options.
This can be useful if you need to target specific phones or tablets to make CSS changes or show certain advertisements for certain devices.
For more options or if you feel like donating, check out the <a href="http://codecanyon.net/item/mobile-css-pro/3182318/" title="Mobile CSS Pro" rel="nofollow ugc">PRO version of Mobile CSS</a> that is available for purchase.

Mobile CSS

Allows you to define different CSS styles that get loaded for specific mobile devices.

mg12

Allows you select another themes that will be sent to mobile users and tablet users.
为手机和平板用户选择另外的主题显示网站内容，手机和平板的主题可分开设定。
Supported Languages:
<ul>
<li>US English/en_US (default)</li>
<li>简体中文/zh_CN (<a href="http://www.neoease.com/" rel="nofollow ugc">mg12</a>)</li>
<li>Slovak/sk_SK (<a href="http://webhostinggeeks.com/blog/" rel="nofollow ugc">Branco Radenovich</a>)</li>
</ul>
Demo:
<a href="http://www.neoease.com/" rel="nofollow ugc">http://www.neoease.com/</a>

WordPress Mobile Themes

Display a mobile theme when the website is viewed with a mobile/tablet browser.

Mobile CSS vs WordPress Mobile Themes