The README file from the Alfresco distribution contains basic info to setup the CIFS server. There are a lot of forum articles also with info, so it might be worth searching in our forums if you get any problems.
We are success using WEbDAv, and implement CIFS under LAN, but in the intranet. and to make new user can use it easily, a drive implementation like CIFS is a cool step, but i cannot find the utility to mount Alfresco become a drive, in internet environment.
right now i am searching a webdav mounting utility for windows.