Hi. I posted an answer a few days back that might help:
Google serves up the same results to smart phones and desktop computers. What they recommend is use the same site and use the style sheet to control the mobile display. In other words, not making a separate site for mobile. Here is a snippet from a Google & A.
John Mueller - @Paul If you have "smartphone" content (which we see as normal web-content, as it's generally a normal HTML page, just tweaked in layout for smaller displays) you can use the rel=canonical to point to your desktop version. This helps us to focus on the desktop version for web-search. When users visit that desktop version with a smartphone, you can redirect them to the mobile version. This works regardless of the URL structure, so you don't need to use subdomains / subdirectories for smartphone-mobile sites. Even better however is to use the same URLs and to show the appropriate version of the content without a redirect :). Here is the entire article where I found the snippet.
The other option would be to make the mobile pages and canonical those back to the corresponding main site pages. This way you don't have duplicate content and you have more SEO juice flow to the main site.
In my opinion, I wouldn't even worry too much about "traditional" cell phones. I found since the beginning of the year, on STP, we've only had 1 or 2 sales via dumb phones and only a fraction of traffic compared with smart phones.