Since a lot of people use phones to browse the Web, it makes a lot of sense to add a mobile interface for Blogger and to create mobile versions for Blogger's templates. There's no mobile Blogger yet, but all Blogger blogs have a mobile version optimized for WebKit browsers. Just add ?m=1 to the URL of any Blogger blog, and you'll get a simplified version that works well on an iPhone, Android phone and probably other phones that use a browser based on WebKit. Here's an example: http://googlesystem.blogspot.com/?m=1.
Bloggers can enable the mobile version of their blogs, so that visitors are automatically redirected to this version when they're using a supported mobile browser. This option is only available if you go to Blogger in Draft, click on "Settings", switch to "Email & Mobile" and enable "Yes, On mobile devices, show the mobile version of my template." This didn't work for me, so you'll still see the regular mobile version of this blog that uses a custom stylesheet.
Google says that the new feature only supports 12 existing templates (6 variants of the Simple template and 6 variants of the Awesome template) and that all the other templates will be rendered as the Simple template. The mobile version drops the sidebars and most of the gadgets, shows small excerpts from the posts on the homepage, hides the comment form (but you can still post comments), resizes images and videos, adjusts fonts and converts AdSense ads into mobile ads. Unfortunately, you can't customize mobile templates, at least not yet.