WPtouch

The WPtouch plugin transforms your blog into a mobile-friendly theme, that can be displayed on the iPhone, Android, iPod Touch, Samsung Touch, Opera Mini, Palm Pre, and BlackBerry Storm/Touch. The plugin gives your blog a mobile option without changing your regular blog theme. Users have the option of switching between the regular theme and the mobile theme.

WPtouch is amazingly full-featured, but with those features comes a bit of complexity. With a little tweaking, you should be able to set up a mobile version of your blog in about 45 minutes. WPtouch is available in both, a free and paid version for about 40 dollars. The free version is remarkably full-featured. Keep in mind, though, that WPtouch is a less desirable alternative to a fully responsive design. But if your site is non-responsive and you don't have the resources for an immediate redesign, WPtouch can serve as a suitable alternative.

You can download WPtouch from http://wordpress.org/extend/plugins/wptouch/.