windows media center isn't needed for xbmc, thats only if you buy M$'s media center remote for xbox. this is for SAMBA: all you need to do is make a windows user for the xbox unless you wanna use your own so long you got a password and then make sure to uncheck "use simple file sharing" (tools-> folder options->view in windows explorer) and then go and right-click any folder/drive you wanna share and make sure the user for the xbox is able to access it, done for pc side of things. now to allow xbmc connect to you pc using the login/password you setup for it you can do this in 2 ways: 1. right in xbmc's settings under network, go to SMB Share and add the info needed (ip and workgroup of pc, username, password) and apply changes. 2. ftp into the xbox and get to xbmc's folder and edit the xml to add the needed info (ip and workgroup of pc, username, password) after that, go into music/videos and choose either (SMB) Network or WORKGROUP (SMB) Network to access your shares i recomend using the latest xbmc since its normally updated daily