Wptouch iPhone WordPress theme plugin is one of the best WordPress plugin I have found to make your blog mobile compatible. This plugin shows mobile compatible theme when a user open your blog from a mobile phone. It also gives an option to switch to original theme.
This is again one of the must have plugin and part of my WordPress plugin list. I have an iPhone and when ever I open my blog on iPhone it loads fine but when I open it on Nokia or symbian powered phone it loads the desktop version of theme. So in simple words it mean: my blog is not showing the mobile version when open from a Nokia or Symbian powered phone.
Here is a quick solution which I have found and work for you as well to make Wp-Touch iPhone theme plugin to load mobile version of site when opened from a Nokia or symbian phone.
Go to this plugin settings and browse down the custom user agent and add this
nokia, iemobile, symbian, maemo
Save the settings and clear you cache and open your blog in Nokia powered phone and you will see mobile version of your site.
Do install this plugin to make your blog mobile compatible. Do share your view about this plugin, if you are using it.