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In case the mobile version of your blog shall have a different layout or when it’s required to load different versions of CSS/JS code.:

This plug-in can overload template files and theme directories - by the detected platform.

And it can provide query_vars 'platform' & 'browser' for creating multi-device templates.

Currently it can detect the following mobile platforms: Android Phones (Android 1.x & 2.x), Android Tablets (Android 3.x & 4.x), Blackberry, iPad, iPhone, iPod, IE mobile, Kindle, SymbianOS, PalmOS, webOS, GoogleBot mobile.

It also can detect several desktop platforms (e.g. Internet Explorer) so it's quite handy for fixing things for specific user-agents (instead of using conditional CSS).

Please be aware the this is a support plug-in, not a fully featured mobile theme.