Here is a list of resources I find useful and I am currently using as my own reference and research:

Mobile Website Development Using DotNetNuke

DotNetNuke Module for converting sites to mobile friendly

Mobile API New features in DotNetNuke 6.1

EasyDNNMobileRedirect Redirects users to a URL based on their mobile device

Mobile Sites on DotNetNuke blog info

Israel Martinez blog posts covering DotNetNuke and webdesign for mobile