By default you have Mobile pages for your SharePoint sites by using /_layouts/mobile/default.aspx at the end of your site URL. If you want to use the shorter /m/ path from a mobile device, you need to run the following STSADM command to activate it on each Site Collection.
stsadm -o activatefeature -name MobilityRedirect -URL http://URL
Referenced Material: http://support.microsoft.com/kb/930147
For Lists or Libraries create a simple View, and when modifying the View scroll to the very bottom of the page is Mobile, expand that and ensure both checkboxes.
For developing mobile pages you should start at the MSDN Mobile site, then there is a tool you can use to emulate the Windows CE hardware behavior here: Emulator (it is the last link on that page).
Additional pages that help with the development are:
Mobile Development with SharePoint Foundation
