It is an ASP.NET open source module which detects mobile devices and provides auto redirection to mobile optimized pages when request is coming from mobile device. It makes use of WURFL mobile device database. For redirection there is no need to modify existing ASP.NET web application pages.
You can very easily define the redirection by simply updating your web.config as per below sample. The below sample allows you to redirect user to mobile device specific pages based on rules created.