The W3C has published a set of guidelines through its Mobile Web Initiative (MWI). The Mobile Web Best Practices 1.0 lays the groundwork with its guidelines for developing and designing websites to work on small handheld devices such as mobile phones.
Similar to the once accessibility debates the document suggest that the idea is to create a single Web, not a separate one designed specifically for mobile devices.
Years ago developers would build a separate text only website for partially sigted viewers with time the guidelines called for a single site that met accessibility guidelines. With the mobile web initiative it is calling for a similar presence of one site developed to be mobile friendly.
Mobile Web Initiative – W3C