Pwntastic.net is the most popular of the 3 user-created music hosting sites used by avid Audiosurfers.
In addition to hosting it's own music, it mirrors the music from the other two sites as well.
The site is moderated through the use of FTP transfers. Any Audiosurfer is allowed access, they need only ask for login information from Pwntastic via message on the Audiosurf forum or via chat on IRC.
That, or you can ask anybody else who has the login information.