I have been struggling to get my mobile theme to show up on iPhone and other phones. It still shows the original theme. It does show up correctly for me on my Android phone, but not for my client. (No idea why not.)
The plugins I have turned on are as follows:
Askimet
All in One SEO Pack
Any Mobile Theme Switcher
Audit Trail
Contact Form 7
Google XML Sitemaps
Open external links in a new window
Realy Simple CAPTCHA
Wordpress Backup to Dropbox
WP Easy Gallery Pro
WP Realtime Sitemap
I like this plugin and would like to find a solution before switching to something else.