A Microsoft representative was quoted in saying the Creator's Club "...will democratize game development by delivering the necessary tools to hobbyists, students, indie developers and studios alike to help them bring their creative game ideas to life while nurturing game development talent, collaboration and sharing that will benefit the entire industry."
User-created games will not be available for distribution to the public immediately, as Microsoft would like to test the service to monitor for potential hazards.
XNA Game Studio Express beta is expected to be released August 30, 2006 while the final version is planned to be launched around the holiday season.
Source:
Gamasutra