It's simple, download the client, install it. Configure the options (especially email address), let it run for a day (make sure blocks are sent to server) then check your e-mail on
http://stats.distributed.net/rc5-64/
You have to wait one day before you are in the database. Once you are registred, you can let the system send you your password (to the e-mail address you used during the setup) by clicking the button at the bottom of the page.
When you received your password, click "edit your information" (you have to supply e-mail and password. this will make a cookie on your system).
When you want to join a team, go to the stats page of the team and click join.
that's it.
check
http://stats.distributed.net/rc5-64/...php3?id=259855 to see my stats