Setup Help Needed

I've got several questions about setting this up properly. I'm using 2.1 beta 2. I'm not using multisite, just a simple membership site where I'm restricting access to one category and a bbpress forum to registered users. I've setup url groups to block the forum.

I want to allow access to the "beta" version of the site for free. Those who participate will get 6 months free membership. After that, they will need to renew annually. What is the best way to set this up?

After my initial testing, is it possible to enable a free trial period (like 15 days)?

Thanks in advance!
Jack