Here's the official announcement:

RetroChallenge 2009 will take place from July 1st to July 31st... the website is currently up at http://www.retrochallenge.net and the BBS can be found at http://telnet://bbs.retrochallenge.net.

Please go to the site and register via the provided email link. Don't forget to include your name (real or otherwise), country and a brief description of what you plan to do.