Use subdomain for mobile user

Hi, I am planning to use subdomain for the mobile user? domain module would be a help. However, how to implement mobile device detection, then redirect to this subdomain? Maybe can use http://drupal.org/project/switchtheme, but haven't try it.

I'm targetting Advanced Mobile browsers i.e iPhone or what else.

1. User different theme. I plan to use simplified theme with only one column. It can contain blocks or $content.
2. Show only certain content as the navigation will be limited. maynot even have primary menu!
3. Have own navigation menu

Importantly we can use the same users, and content. Any advise or comment?