There are several smart phone virii that can spread by MMS, bluetooth, through web browsing or email. They're fairly few and far between because mobile phones, unlike computers, use many different proprietary operating systems. As far as I know Symbian virii are the most common which is used by Nokia and a few others. All mobile device virii I've ever heard of require the user to actively accept the installation of an executable script so savvy users are less likely to install something called 'Very important update' or 'please install me' or important warning' which might have an ELF file extension for example.

Also for a virus writer a good Windows virus would carry the most kudos, not for complexity or technical reasons, just because it's M1crosoft, the sworn enemy.

I know Kaspersky and Symantec distribute AV products for portable devices and I'm sure there's many more.