If you go to
http://groups.google.com/group/openscienceframework, click the "Sign in" link in the top right of your browser. This is the same page that you will see if you are asked to sign-in (for example, you are trying to comment or post a message). At this point, click "Sign up for a new Google Account" on the top right of your browser. You can use existing email accounts by selecting the appropriate box in the "Use your email provider" column. Many will select "Use a different email" and follow the instructions from there. At this point, you can come back to
http://groups.google.com/group/openscienceframework and join in on the discussions.