If you want to participate in the private beta, just go to the download section and download the extensions for ArgusCache. All beta testers that contribute to the improvement of the product are entitled to a 50% discount for the first year of usage.
If you want to participate in the Beta, please sign up for the ArgusCache Google Group and report issues via mail to firstname.lastname@example.org. We will send out a questionnaire to all participants in order to make ArgusCache the best tool for your performance optimizations and for handling performance issues with your legacy applications.
We will soon launch a bug reporting tool which we will either blog about in our Rasia Blog or annouce it in the Google Group.