In Windows 2000, getting to the Sharing options for a folder was simple: Just right-click, choose Properties, and you'd see a Sharing tab. In Windows XP, this seems to be missing, and the Beta 2 trick to displaying it (hold down CTRL as you right-click) no longer works.
But fear not, you can still cause your Windows XP RC1 or RC 2 system to display the Sharing tab if desired. Simply open up Folder Options (My Computer, then Tools, Folder Options) and navigate to the View tab. In the Advanced Settings section, scroll down to the bottom and uncheck Use simple file sharing (Recommended), a Mickey Mouse feature if there ever was one. Now share your folders on the LAN as you would in Windows 2000.