Upload content to share with other con attendees (needless to say, you may want to trust content hosted by DEF CON more than random stuff shared by con attendees).

NETDrive (http://www.netdrive.net/download.html) is windows software that will allow you to easily map a drive via WebDav.
This software was also provided for you on the DC20 Conference CD.

NetDrive Settings:

Site Name: dc20-media.defcon.org
Site IP:
Port: 21
Server Type: FTP
Drive: "select a drive letter"
Account: connect as anonymous
(if you don't select anonymous, it will prompt you for a login; that means you're doing it wrong)

Under Advanced: force SSL for all communications.